1:34 I saw. John gives his final, definitive answer to the Pharisees who were challenging his right to baptize in water. God Himself had sent him to do so (John 1:33), so that when Jesus also would come for baptism (Luke 3:21-22) to “fulfil all righteousness” (Matthew 3:15), God could identify Him by sending the Holy Spirit upon Him in the form of a dove (John 1:32-33), in order that “He should be made manifest to Israel” (John 1:31).
1:34 bare record. Six times in this first chapter, John the Baptist “bears witness” concerning Christ (John 1:7,8,15,19,32,34).
1:34 Son of God. John thus recognizes Jesus Christ as Creator (John 1:1), as the life and light of all men (John 1:4, 9), as the Word incarnate (John 1:14), as preexistent (John 1:15,30), as the One bringing God’s grace and truth into the world (John 1:14,17), as the Savior of those who believe (John 1:12), as the One in whom sinners could be born again to become children of God (John 1:13), as the One who reveals the Father (John 1:18), as the only begotten Son of God (John 1:14,18), as the sin-bearing, sin-removing Lamb of God (John 1:29), and as the One who would baptize with the Holy Spirit (John 1:33). This is surely a fully developed Christology, not an Old Testament prophecy, as many expositors have claimed. John was indeed a prophet, but not of the Old Testament. John the Baptist was the first Christian prophet, the first Christian gospel preacher, the first to administer Christian baptism, the first Christian witness, the first Christian filled with the Spirit, the first Christian missionary, the first Christian pastor and, finally, the first Christian martyr! It is remarkable that so few Christians recognize his unique greatness, as Christ did (Matthew 11:9-11).