One of the things I love about learning to study the book of John in koine Greek is the way John creates his narrative. Everything goes together like pieces of a puzzle that is not immediately apparent to me in English but stands out sharply in the original Greek.
In the early verses, John has made a clear statement that Jesus is the Word that existed with God in the beginning, was God and was the method by which all things were created. He has stated that the Word became flesh and pitched his tent with us, living among us. He has said that life was in HIm and that life was the light of men. He has clearly concluded that, to those who believe, he has given the right, authority, power to become children of God.
In verse 29, he introduces a new concept. "The next day, he saw Jesus coming toward him and he said, "Behold, the lamb of God that lifts away the sins of the world." The words "τοῦ κόσμου" that we translate "the world" refer to God's created order, suggesting that Jesus lifts the sins away from His creation, restoring order. Although τοῦ κόσμου may be metaphorically describing people collectively, this deeper suggestion is carried in the language, that by lifting the sins of humankind, God is restoring order to His creation.
Τῇ ἐπαύριον βλέπει τὸν Ἰησοῦν ἐρχόμενον πρὸς αὐτόν, καὶ λέγει, Ἴδε ὁ ἀμνὸς τοῦ θεοῦ ὁ αἴρων τὴν ἁμαρτίαν τοῦ κόσμου.
By verse 34, John states, "I have seen and witnessed that this is the Son of God."
κἀγὼ ἑώρακα, καὶ μεμαρτύρηκα ὅτι οὗτός ἐστιν ὁ υἱὸς τοῦ θεοῦ.
Then, in 35 and 36, we read, "The next day, again, John was standing with two of his disciples and said, "This is the Lamb of God." He restates for emphasis that Jesus is the Lamb of God.
Τῇ ἐπαύριον πάλιν εἱστήκει ὁ Ἰωάννης καὶ ἐκ τῶν μαθητῶν αὐτοῦ δύο, καὶ ἐμβλέψας τῷ Ἰησοῦ περιπατοῦντι λέγει, Ἴδε ὁ ἀμνὸς τοῦ θεοῦ.
John has already clearly stated in earlier verses that Jesus is God, that Jesus is the unique (there's only one) son who is in the bosom of the father, that no one has ever seen God, and that the unique Son of God who is in the bosom of the Father has fully revealed Him.
Now, He is pivoting completely, referring to Jesus as The Lamb of God one day, explaining that He is God immediately afterwards and, one day later, referring to Him as the Lamb of God again.
John is making a connection for the minds of his Jewish readers to follow. One of the most important Jewish holidays to date is the Passover, where the blood of a sacrificial lamb was spread on the doorposts of the Jews in Egypt so the angel of death would pass over their houses when taking the lives of the firstborn children of Egypt. John is connecting the sacrificial lamb to God in a different way.
By verse 36, John has strongly laid the argument down that God came down in the flesh and lived among us, all the reveal God's plan to humankind and the execute that plan. The message was, and is, that God desires reconciliation with humankind. God desires a restoration of humans to their true purpose, an end to our rebellion that leads ultimately to our death and destruction.
To that end, God came down in the flesh and became the ultimate sacrifice for the sins of humankind that plagued the world. It's the ultimate get out of jail free card to humans, an invitation to believe, turn away from sin and live out our true purpose. That purpose is to love God, love our fellow humans and take care of the world that God created.
It is the primal simplicity that Lao Tzu wrote about, the taming of the chaos, the restoration of the hearts and minds of humankind so that we may live as children of God and be the likeness of God in His created order.
All is takes is for you and I to believe, to receive and walk the path, spending our lives learning and becoming children of God.