What does the Bible say about judgment day?

Acts 17:30-31 emphasizes the certainty of a judgment day appointed by God, where all men are called to repent due to the assurance of this day given through Jesus’ resurrection. Hebrews 9:27 also affirms that it is appointed unto men once to die, followed by judgment. This day is significant as it represents God's righteous judgment, highlighting that each individual will stand before God to account for their lives, as illustrated in Revelation 20:11-15, where the dead are judged according to their works.