In ancient Hebrew religious practice, God gave rules about what was "clean" (acceptable to God) and "unclean" (not acceptable to God). These rules affected different parts of life:
Physical cleanness: rules about the body, food, and daily life
Religious ritual cleanness: rules about worship and ceremonies
Moral cleanness: rules about right and wrong behavior
Spiritual cleanness: rules about having a right relationship with God
These different types of cleanness were connected. For example, following the physical rules about clean and unclean things showed that a person wanted to be pure in their heart and close to God.
The Old Testament shows that God wanted to have a close relationship with his people. He showed this by giving his laws to Moses. These laws helped people understand what God was like and how he wanted them to live.
God was different from the false gods that other nations worshiped. The Canaanites worshiped gods called Baals, who were unpredictable and cruel. No one expected these false gods to be reliable or to do what was right.
But the Lord, Israel's God, was different. God always:
Kept his promises
Spoke clearly through his chosen prophets
Treated everyone equally under his law
The law showed both God's character and his plan for individuals and the whole nation. Everyone had to follow God's law, even the high priest and the king.
God also showed his faithfulness by acting in history to:
Protect his people
Judge those who did wrong (both his people and their enemies)
Work out his plan to save all people
The book of Leviticus explains what it means to be "clean" before God. Since God himself gave these laws, people had to follow his rules when they wanted to approach him in worship. He gave them specific religious rituals to follow. These rituals had two purposes:
To show people how sinners (those who did wrong) could come to God
To show how God made a way for his people to become pure and acceptable to him
This system of cleanness was described in the Psalms: “Who may ascend the hill of the LORD? Who may stand in His holy place? He who has clean hands and a pure heart, who does not lift up his soul to an idol or swear deceitfully.” (Psalm 24:3–4). Being clean before God depends on two things:
What people do on the outside
Their personal connection with God in their heart
No one can perfectly follow all of God's rules about right and wrong. This means people must depend completely on God's help. In God's law, God explained how he would help people become clean and acceptable to him.
Preview
- Early History: How Did These Rules Begin?
- Laws from Leviticus: What Did God Command About Being Clean?
- Purification Ceremonies: How Did People Become Clean Again?
- New Testament Perspective: What Did Jesus Teach About Cleanness?
Early History: How Did These Rules Begin?
Non-Jewish Religious Background
Many ancient cultures had their own ideas about what was clean and unclean. People who were not Jewish (called "gentiles") influenced how these ideas developed.
In every major religion around the world, people felt that doing wrong things made them unclean. Many religions had special ceremonies to make people clean again, often using water for washing.
The Hebrew people (ancient Jews) had rules about staying away from certain things:
Some things because they were too holy
Other things because they were unclean
These rules were similar to the forbidden practices in other ancient religions, including some religions that the early Hebrew people encountered.
When we compare the ancient Hebrew religion with other ancient religions, we can easily see some similarities. This is not surprising. However, the Hebrew religion also had many unique features that made it different from other religions. These differences are important to understand.
Laws from Leviticus: What Did God Command About Being Clean?
Ceremonial and Moral Law
In the Old Testament, there is a strong connection between the external ceremonial laws of Moses and the moral requirements, such as the Ten Commandments. Throughout the Old Testament, uncleanness and sin are often considered the same. Many passages describe sin as uncleanness (for example, Leviticus 16:16, 30; Numbers 5:11–28; Zechariah 13:1).
The relationship between ceremonial and moral cleanness can be seen in:
Passages mentioning clean hands (2 Samuel 22:21; Job 17:9; 22:30)
Passages mentioning a clean heart (Psalms 24:4; 51:10; 73:13; Proverbs 20:9)
The prophet Isaiah felt like he had “unclean lips” when he was in God’s presence. God touched his lips with a burning coal to make him clean. This showed that God had forgiven him (Isaiah 6:5–7).
When someone is clean before God, it means they are doing what is right (Job 11:4; 33:9; Psalm 51:7–10; Proverbs 20:9). When someone does wrong things against God, it makes them unclean (Psalm 51:2; Isaiah 1:16; 64:6).
Causes of Uncleanness
In the laws that God gave to Moses, we can find many things that made people unclean:
Forbidden Foods: Some foods were not allowed. Laws about animals “distinguish between the unclean and the clean, between animals that may be eaten and those that may not” (Leviticus 11:47). God allowed his people to eat only the foods that he approved (see also Deuteronomy 14:3–21; Acts 15:28–29).
Diseases: Some diseases made people unclean according to God's law, especially leprosy (Leviticus 13–14). In Bible times, many different skin problems were called leprosy, including swellings, sores, rashes, and the disease we now call leprosy. Naaman was healed from leprosy (2 Kings 5:1–14). Jesus healed many people with leprosy (for example, Matthew 8:1–4; 10:8; 11:5; Luke 4:27). When someone had one of these diseases, everything they touched also became unclean (Leviticus 14:33–57).
Bodily discharges: God's law had rules about body fluids making people unclean for different amounts of time. When a man released bodily fluid during sexual relations or accidentally during sleep, he would be unclean until evening (Leviticus 15:16–18; Deuteronomy 23:10).
If someone had an unusual fluid from their body because of illness, they would be unclean for seven days after it stopped (Leviticus 15:1–15).
Menstruation (monthly bleeding) caused uncleanness for seven days after it had ended (Leviticus 15:19–24; 2 Samuel 11:4). Sexual intercourse during menstruation made both partners unclean (Leviticus 15:19–24; 20:18).
If an unclean person's spit touched someone, that person would be unclean for one day (Leviticus 15:8).
Corpses: Dead bodies, even only a part, caused uncleanness (Numbers 19:16). People who touched a dead body were unclean for a month. They would have to delay Passover if they missed it due to uncleanness (Numbers 9:6–11). The high priest was not allowed to bury his parents because of his special duties (Leviticus 21:10–11; compare Numbers 6:6–7; Haggai 2:13; Matthew 23:27).
Idolatry: The worship of false gods (idolatry) was the worst thing that could make people unclean before God. The whole nation of Israel could be made unclean because of idolatry (Psalm 106:38; Isaiah 30:22; Ezra 36:25). Non-Jewish people were also made unclean by idolatry (Jeremiah 43:12).
Because of this, Jewish people believed that contact with non-Jewish people would make them unclean. But when Jesus came, his message was for everyone. This challenged the old belief about staying separate from non-Jewish people (John 4:9; Acts 10:28; compare Galatians 2:11–14).
Evil spirits could also make people unclean (Zechariah 13:2; Matthew 10:1; Mark 1:23–27).
Laws About Objects
Uncleanness could spread from one thing to another, like a disease. Dead bodies and insects infected whatever they touched (Leviticus 11:29–38). Only dry grain, water from springs, and water in a cistern could not become unclean. This rule helped people survive since farming communities often found dead insects and mice in their food and water.
Unclean pottery had to be broken, but wooden vessels needed to be washed (Leviticus 15:12). Even uncovered pots in a house where someone had died became unclean (Numbers 19:15). Everyone inside of the house also became unclean.
Things that belonged to people who worshiped false gods were considered unclean. When the Israelites captured items in war, they had to clean these items. They cleaned these items by putting them through fire or washing them with water (Numbers 31:21–24).
Clothes could also become unclean with a type of disease called "leprosy." This could affect wool clothing, linen clothing, and leather items. When clothing showed signs of disease (green or red patches), people had to test it. If these patches spread after the test period, they had to burn the clothing (Leviticus 13:47–59; 14:33–53).
Laws About Places
The land and people of Israel were holy, but they could become unclean by oppression or idolatry (Joshua 22:17–19; Jeremiah 13:27). Jerusalem was a holy city, but it could become unclean by the sins of its people (Ezra 22:2–4; Lamentations 1:8). It could also become unclean by the blood of the people who lived there (Lamentations 4:15).
Unclean people could make the temple unclean. For example:
Hezekiah needed to cleanse the temple after Ahaz’s idolatry (2 Chronicles 29:15–19).
Nehemiah had to cleanse the rooms that Tobiah lived in (Nehemiah 13:9).
The Day of Atonement was a time to remove the impurities of the temple caused by the Israelites' sins (Leviticus 16:16–19; 31–33).
After its destruction, the pieces of a leprous house had to be placed in an unclean place (Leviticus 14:45). The valley of Hinnom was a garbage dump in later years. It became a symbol for “Gehenna,” a place of eternal punishment in the New Testament. The Israelite camp was a holy place. So, human waste was buried outside its boundaries (Deuteronomy 23:12–14). This prevented disease during battles, which is important because plagues were a problem in ancient armies.
Laws About Food
Certain animals were unclean and could not be eaten (Leviticus 11; Deuteronomy 14:3–21). Animals were unclean if they died from:
Old age
Disease
Injury
Animals that predators had wounded were also unclean.
Only animals that chewed the cud (chewed their food twice) and had cloven (split) hooves were clean. This meant many animals could not be eaten, such as:
Pigs
Camels
Badgers
Rabbits
Israelites could eat only those fish that had both fins and scales. Birds of prey, scavengers, and all winged insects were unclean except for hopping insects like:
Grasshoppers
Crickets
Many “crawling things” were unclean, including:
Worms
Lizards
Snakes
Weasels
Mice
Eating blood was also forbidden (Genesis 9:4; Leviticus 17:14–15; Deuteronomy 12:16–23; Acts 15:28–29).
Purification Ceremonies: How Did People Become Clean Again?
Purification by Waiting
God's law gave different waiting periods before people could become clean again. Many cases of touching unclean things only lasted until evening (Leviticus 11:24). Anyone or anything that touched a dead body was unclean for seven days (Numbers 19:11).
During a woman's monthly bleeding, she was unclean for seven days (Leviticus 15:19). This was also true of anyone who touched her. When a mother gave birth, she was unclean for seven days for a boy and 14 days for a girl. The mother would have to wait another 33 days for a boy and 66 days for a girl before she could touch holy things.
Purification by Water
Touching unclean things (like bodily fluids) required washing hands and clothing, as well as waiting a day before being considered clean again (Leviticus 15:5–11).
Purification by Ceremonial Substances
Certain substances were used in purification ceremonies, such as:
The ashes of a red heifer mixed with water (Numbers 19:1–10)
Cedarwood
Scarlet cloth
Blood was the only thing that could purify the altar because the altar was the place of sacrifice for sin (Leviticus 16:18–19; Ezra 43:20).
Purification by Sacrifice
The main way people became clean again was by bringing sacrifices to God. Different situations required different sacrifices. Bodily discharges, except those from sexual activity, were purified by offerings of doves and pigeons (Leviticus 15:14–15, 29–30). Childbirth required a lamb and a bird to be sacrificed (12:6). Those who were poor could offer birds in place of an animal (Leviticus 12:8; 14:21–32; Luke 2:24).
In sacrifice, blood symbolizes life. So, giving blood represented death. The uncleanness of disease was transferred to the victim, removing the uncleanness (Leviticus 14:7). The victim substituted for the sinner. This substitution was key because only blood sacrifices could provide the moral cleansing needed for sin. So, blood sacrifice was the basis of all cleansing, including from disease.
Purification by Fire
Some uncleanness could only be removed by fire. For example:
Unclean metal pots could only become clean again by being put through fire (Numbers 31:22–23).
Incest was punishable by death, and the bodies needed to be burned (Leviticus 20:14).
Idolatry required the total destruction of the objects by burning (Exodus 32:20).
Cities dedicated to foreign gods had to be burned.
New Testament Perspective: What Did Jesus Teach About Cleanness?
The New Testament did not reject what the Old Testament taught about clean and unclean things. Instead, it gave these teachings new meaning. The New Testament emphasized the moral meaning of the concept and connected uncleanness with sin.
The Gospels were written in the context of Old Testament laws and their interpretation by the Pharisees and Sadducees. Jesus obeyed the law but challenged the rules that had developed around it. Jesus taught that uncleanness came from the heart and not from outside forces (Mark 7:14–23; Luke 11:39–41). He criticized the Pharisees for focusing on outward ceremonies. Some say Jesus “internalized” the law, but it is more accurate to say he drew attention to how the law applies to a person’s inner life.
In the Gospels, evil spirits are always called "unclean spirits." This shows that they are completely evil. It's important to notice that in these books, the word "unclean" is only used when talking about evil spirits. This shows how the New Testament changed its focus. Instead of talking mainly about being physically unclean, it focused more on spiritual problems like sin and guilt.
An important event happened in the early Christian church (Acts 10). God showed Peter, one of Jesus's closest followers, that non-Jewish people (called "gentiles") were not unclean. God wanted Peter to welcome them into the church. Because of this, a man named Cornelius, who was not Jewish, became one of the first gentile followers of Jesus.
Jesus taught that uncleanness comes from what is in a person's heart, not just from breaking religious rules. This teaching influenced Paul, who later wrote many letters in the New Testament. Paul, a Pharisee who was faithful to the law, taught that nothing is unclean in itself (Romans 14:14–20). In his letters, Paul taught that people become clean in a new way:
Through obeying God from their heart
Through being made new by God (called "regeneration")
Through Jesus's death, which has the power to make people clean from sin
Paul emphasized that being unclean was about doing wrong, not about breaking religious rules (see Romans 6:19; 1 Thessalonians 2:3–4).
Jesus's death on the cross was the final and complete way to make people clean from their sins (Hebrews 9:14, 22; 1 John 1:7). In the Old Testament, people sacrificed bulls and goats, but these sacrifices only pointed to what Jesus would do later. The Bible uses symbolic language to describe this:
People who trust in Jesus are "washed… in the blood of the Lamb" (Revelation 7:14).
When Jesus died, he gave his blood (his life) because God the Father asked him to. This met all of God's requirements for justice. Because Jesus showed that God the Father is completely right and good, God can now forgive people who have done wrong. This matches who God has always been and always will be. God is both perfectly just (does what is right) and the one who makes people right with himself when they believe in Jesus (Romans 3:24–26).