Final answer:
The two disciples mentioned in the question followed Jesus after hearing John the Baptist's proclamation.
Step-by-step explanation:
When the two disciples heard John say 'Behold the Lamb of God,' they followed Jesus. This event is described in the Gospel of John, where John the Baptist points his own disciples to Jesus, recognizing Him as the Messiah. One of the disciples who followed Jesus was Andrew, who later brought his brother Simon Peter to meet Jesus. The other disciple is not named in the text. Following Jesus meant becoming His disciples, learning from Him, and spreading His teachings.