John the Baptist is a man sent from God
John the Baptist and all the prophets are men sent from God. They speak for God. We must listen to them because they speak for God to us. All the prophets point to Jesus as the only way to the Father. John comes from God and points us to Christ.
John the Baptist is a witness
A witness simply states what they have heard and seen. They repeat what they have been told. They seek to simply tell what is true. John does not come to create a following, make a name for himself, or any such thing. He simply comes to proclaim the truth concerning Jesus. John the Baptist is not the one who changes people and brings them out of their darkness. Instead he simply proclaims the Truth (Jesus) and the Truth sets people free (John 8:32). He simply tells people of the Light (Jesus) and the Light brings them out of their darkness.
Jesus alone is the Light
The Apostle John is setting up a great contrast between John the Baptist (along with all the prophets) and Jesus. John the Baptist, like all the prophets, was simply a man sent from God. Jesus, on the other hand, is God Who became a man. The Apostle John will not allow that Jesus is simply a great man that God sent. Jesus is God Who became a man. Jesus is greater than the greatest of all prophets; He is the Subject of all their prophecies (John 5:39). As great as John was, he was not the Light. He was a man who needed Jesus (Matthew 3:13-14). Jesus alone is the Light of the world. All hope must be placed in Jesus, not man. Jesus alone can save man from his sin.
John the Baptist came to bring people to faith in Christ
The purpose of John the Baptist’s testimony is to bring people to faith in Christ. That is the whole point of his life and ministry. He is to prepare men’s heart for the coming Savior. When Christ appears, John immediately points them to Jesus as the Lamb of God that takes away their sin.
All the prophets are men sent from God who point to Jesus. To truly follow Jesus you must be in line with all of Scripture; to be in line with all of Scripture you must truly follow Jesus. You must either receive all of the Scriptures or reject them all. You cannot pick and choose what verses you like and dislike.
We are to simply be witnesses. Our duty is simply to proclaim the truth concerning Jesus. It is the Spirit’s job to convict men and bring them to salvation. It is God’s duty to judge, and it is our duty to proclaim what He has judged and how He will judge.
We are not the Light. We are only the light of the world in that Jesus Christ indwells His people. We are to point people to Christ by letting His Light be seen through us. We must proclaim the Truth (Jesus) and the Word (Jesus).
We must believe the whole testimony of Scripture concerning Jesus Christ. As John the Baptist testifies, Jesus is the Lamb of God that takes away our sin. We must believe in Him.