The next day John saw Jesus coming toward him, and said, “Behold! The Lamb of God who takes away the sin of the world! This is He of whom I said, ‘After me comes a Man who is preferred before me, for He was before me.’ I did not know Him; but that He should be revealed to Israel, therefore I came baptizing with water.”
And John bore witness, saying, “I saw the Spirit descending from heaven like a dove, and He remained upon Him. I did not know Him, but He who sent me to baptize with water said to me, ‘Upon whom you see the Spirit descending, and remaining on Him, this is He who baptizes with the Holy Spirit.’ And I have seen and testified that this is the Son of God.”
The occasion of the public baptism recorded for all future generations the perfect embodiment of the triune God revealed in glory from heaven. The testimony directly from heaven of the Father’s pleasure with the Son and the descending of the Holy Spirit upon Jesus (Matthew 3:16-17) is a beautiful picture of the trinitarian nature of God. It also depicts the work of the Father, Son, and Spirit in the salvation of those Jesus came to save. The Father loves the elect from before the foundation of the world (Ephesians 1:4); He sends His Son to seek and save the lost (Luke 19:10); and the Spirit convicts of sin (John 16:8) and draws the believer to the Father through the Son. All the glorious truth of the mercy of God through Jesus Christ is on display at His baptism.
(Retrieved from Got Questions)