What does John 1:29 mean?
Verse 29 uses the fourth of John's seven names for Jesus, "The Lamb of God." Lambs were required as a yearly sacrifice for all Jewish families. This was for the celebration of Passover. This holiday looked back to the days of Moses, when lambs' blood covered the doors of Israel, and allowed God's judgment to "pass over" them (Exodus 12:22–23). Isaiah 53:12 predicted that the Messiah would "bear the sins of many." The connection to Passover is the primary reason Jesus is referred to as "The Lamb of God." His crucifixion also symbolizes other Old Testament sacrifices. Instead of a lamb, the sin offering specified in the book of Leviticus is a goat. Lambs were sacrificed in the temple for Passover, but goats were cast out of the camp. Jesus will be taken outside the walls of the city to be sacrificed on the cross.This verse is also the first of seven "witnesses" in the gospel of John. These are people who specifically state that Jesus is the Christ, the Messiah, the Son of God. The others include Nathanael (John 1:49), Peter (John 6:69), the blind man (John 9:35–38), Martha (John 11:27), Thomas (John 20:28), and Jesus Himself (John 5:25; John 10:36).
The events of verse 29 occur the day after the Baptist's conversation with the Pharisees' messengers. It's likely that many of the same people were there once again.