Anything that causes pain or distress, such as a calamity.
According to the Bible, affliction began when sin entered the world. Both humanity and all of creation became afflicted with "thorns and thistles," sin, death, and decay (compare Genesis 3:16–19; Romans 8:18–21). Because of sin, misery is a common human experience, and our short lives are filled with trouble (Job 14:1–6). People cannot avoid natural disasters, physical injuries, and conflicts with others (2 Chronicles 20:9). Yet, God uses affliction to teach and discipline his people. This affliction is shown by the oppression the Israelites faced in:
Egypt (Exodus 4:31)
Their struggles during the judges (Nehemiah 9:26–27)
Their exile in Babylon (Isaiah 26:16)
In their distress, the Israelites cried out to God. He delivered them and guided them to obey (Jeremiah 10:18; Hosea 5:15–6:3).
The Bible knows it is hard to understand. It is hard to see why the righteous suffer so (Psalms 34:19; 37:39; 138:7). Even the prophet and “Servant of the Lord” (the Messiah) were not spared (Isaiah 53:2–12; Jeremiah 15:15). Jesus Christ carried humanity's griefs and sorrows. He fulfilled the prophecy of affliction that began with Adam's sin (Isaiah 53:4–5; 1 Peter 2:24).
Jesus warned that his followers would face many trials and sorrows (John 16:33). Paul taught that entering God's kingdom comes with many troubles (Acts 14:22). But these should not weaken a Christian's faith (1 Thessalonians 3:3). They should be seen as completing what is lacking in Christ's sufferings for his body, the church (2 Corinthians 4:10–11; Colossians 1:24). The Bible also suggests that affliction will become more intense as "the end" approaches (Matthew 24:9–14; 2 Timothy 3:13). Satan's forces will attack to deceive and destroy the "elect" (Matthew 24:24; 2 Thessalonians 2:9–12; Revelation 20:7–9). When Jesus Christ is revealed from heaven in flaming fire, God will afflict those who have harmed believers. He will take vengeance on those who have not obeyed the gospel of Jesus Christ (Romans 2:9; 2 Thessalonians 1:5–10; 2:7–8).