“The next day John saw Jesus coming toward him and said, “Here is the Lamb of God, who takes away the sin of the world! This is the One I told you about: ‘After me comes a man who has surpassed me, because He existed before me.’ I didn’t know Him, but I came baptizing with water so He might be revealed to Israel.” And John testified, “I watched the Spirit descending from heaven like a dove, and He rested on Him. I didn’t know Him, but He who sent me to baptize with water told me, ‘The One you see the Spirit descending and resting on — He is the One who baptizes with the Holy Spirit.’ I have seen and testified that He is the Son of God! ” Again the next day, John was standing with two of his disciples. When he saw Jesus passing by, he said, “Look! The Lamb of God! ” John 1:29‭-‬36

The next day–the day after John the Baptiser (JB) was questioned by the Pharisees–the religous leaders of the day about who he was, why he was baptising and who he represented. The next day-the day after he answered that he was the forerunner of his Younger Cousin, Who according to JB pre-dated him (because Jesus, as God pre-existed eternity.)
So, the next day, JB saw Jesus walk by. He points to Jesus and loudly announced Jesus as, “the Lamb of God Who takes away the world’s sins”. As Jesus’ forerunner, the one who prepared the way for Jesus, the one who introduced Him to the watching world, what was JB saying with this introduction–Who was the Lamb of God?
Maybe he was refering to the passage in Isaiah the described Jesus as, “a lamb led to the slaughter and like a sheep silent before her shearers, He did not open His mouth.  (Isaiah 53:7)
Perhaps he was remembering what Abraham said to his son Isaac, when Isaac asked, dad, where’s the sacrifice? Abraham answered, “God Himself will provide the lamb for the burnt offering, my son.” (Genesis 22:8 )
Maybe JB was remembering the Passover Lamb Whose life was taken and blood was painted on and

above the door posts to detour the death angel who had been sent to kill the first-born son of EVERY family in Eygpt when the last plague was put upon the land in order to convice Pharoah to release the Nation of Israel from slavery (Exodus 11-12).
Regardless of what he was thinking about, JB properly introduces Jesus! He says, there He is, the Lamb of God–our sin-bearer. JB might as well have said, “Guys, there’s your Messiah”!
Then JB further explain that it was on Jesus that he “watched the Spirit descending from heaven like a dove and He rested on Him. . .” Continuing to explain that God had told him that ‘The One you see the Spirit descending and resting on — He is the One who baptizes with the Holy Spirit.’ (vs 33)
JB pulled no punches when intoducing Jesus as the Messiah or God, (the One who had the right to distribute the anointing of Holy Spirit) (vs 34)!
How plainly do we introduce Jesus our World-Changer today?
Think about it!