A vision is when someone sees something with their eyes or in their mind. In the Bible, visions usually mean special messages that God showed to prophets.
Types of Visions
Visions About the Present
In early Old Testament prophecy (when prophets first began speaking God's messages), there are examples of special sight that others did not have. The people saw this special sight as proof that someone was truly a prophet of God.
Samuel was a "seer" or visionary. He was able to "see" where Saul’s lost donkeys were and to tell him where they were (1 Samuel 9:19–20). Elisha was able to follow Gehazi’s wrongful actions "in spirit" and confront him on his return (2 Kings 5:26). This special ability to see things was a gift from God that he gave only to his prophets. These visions showed the prophets things that were happening on earth at that time.
Visions About the Future
God also gave prophets revelatory visions that showed things about the future. Sometimes, God shared these messages through dreams. Both visions and dreams were true ways that God revealed things to His prophets. The main difference seems to be that visions happened during the day, while dreams came during sleep.
There are different types of revelatory vision. One type was when God's Spirit completely took over the prophet's senses. For example, Ezekiel could be spiritually moved to different places while in this special state (Ezekiel 8:3; 40:2). Daniel’s vision in Daniel 8 was probably of the same type, and so perhaps was Jeremiah’s experience in Jeremiah 13:4–7.
Visions of Ordinary Things with Special Meaning
Another type was when God helped prophets see deeper meaning in ordinary things. For instance, God showed Amos a basket of summer fruit, but it had special meaning. God "caused" Amos "to see" the basket (Amos 8:1–2). Jeremiah had similar visions when God showed him an almond branch and a pot that was tipping over (Jeremiah 1:11–13).
Heavenly Visions
There was also a middle type of vision, where prophets saw pictures of heavenly things. Isaiah saw visions of heaven (1 Kings 22:19–22; Isaiah 6). The apostle John had similar visions when he wrote the book of Revelation.
How God Communicated Through Visions
Prophets could receive God's messages by seeing things or by hearing God's voice. Typically, a spoken message was communicated with an image the prophet could see so that the seeing and hearing took place at the same time. This was the case with Isaiah, who both "saw the Lord" and heard his voice.
Sometimes, even when prophets only heard God's voice, people called it a "vision" because it was still a message from God. In many places in the Bible, it is hard to tell if "vision" means the prophet mostly saw something or if it just means they received any kind of message from God (for example Ezekiel 12:21–28). Often, "vision" is used simply as a technical term for any message from God, even if it was just words the prophet heard. When God first called Samuel to be a prophet, the Bible specifically uses the word "vision" to describe this event (1 Samuel 3:15).
The prophetic books in the Bible contain messages from God delivered through prophets and often include visions, warnings, and promises. Several of the prophetic books have the word "vision" in their first verse (Isaiah 1:1; Obadiah 1:1; Nahum 1:1). When Nathan told David about God's special promise to him (God's covenant), this message is also called a "vision (2 Samuel 7:17; 1 Chronicles 17:15; Psalms 89:19). In Daniel 9:24 "to seal both vision and prophet" means to confirm that Jeremiah's prophecy (mentioned in verse 2) was true and would happen.
There is a famous verse in Proverbs that says, "Where there is no vision, the people cast off restraint" (Proverbs 29:18). In this verse, "vision" means the messages God gave through prophets. These prophetic messages were meant to help guide the people of Israel in how to live.