The term "Lamb of God" refers to Jesus as a sacrificial lamb who takes away the sins of the world. In the Old Testament, lambs were often used as sacrifices to atone for sins. Jesus, being the Lamb of God, is the ultimate sacrifice, as he willingly gave up his life to pay the penalty for the sins of humanity. This signifies that Jesus was to bear the sins of the world like a paschal lamb. Through his sacrifice, he offers salvation to those who believe in him.