You may wonder why Jesus Christ who is the son of God - holy, spotless, and pure yet chose to be baptized on earth. As we know John's baptism was for repentance and remission of sin; meanwhile Christ was not repentant for any evil act seeing that He kept the law and was justified.
Bro Eli's teaching carefully pointed out the significance of His baptism despite being a sinless Christ. He pointed that in Matthew 3:13-15 baptism was seen to be the fulfilment of what was written in the scriptures for Christ.
KJV:Then cometh Jesus from Galilee to Jordan unto John, to be baptized of him.
KJV:But John forbad him, saying, I have need to be baptized of thee, and comest thou to me?
KJV:And Jesus answering said unto him, Suffer it to be so now: for thus it becometh us to fulfil all righteousness. Then he suffered him.
The scripture, Matthew 3:13-15 showed that John did not feel worthy to baptize Jesus but for sake of fulfilling all righteousness just as Jesus said in verse 15, he decided to baptize Him.
Still on Bro Eli's teaching I got to understand that whatever Jesus did were according to what He came on earth to fulfill. In Hebrews 10:7, we could understand the assignments that were unique for for Christ to fulfill and it was clearly recorded; the good part is that He fulfilled all that the father commissioned Him to do (baptism was inclusive).
KJV:Then said I, Lo, I come (in the volume of the book it is written of me,) to do thy will, O God. Hebrews 10:7
Which means Jesus came to earth baed on the will of His father. You can affirm this in His prayer at Gethsemane - "...not my will, but thy will." was the statement Jesus made for us to understand that He did not come on His own, but came according to what was written about Him.
Similarly in the book of Luke 24:44, Bro Eli added that these fulfillment of prophecies were written by the prophets of old testament, and Jesus fulfilled them all.
KJV:And he said unto them, These are the words which I spake unto you, while I was yet with you, that all things must be fulfilled, which were written in the law of Moses, and in the prophets, and in the psalms, concerning me.
Clearly, this gave us to understand the reason why there was a need for John to baptise Christ - to fulfil what was written of Him.
Even in the life of John, prophecies were made of his coming and he eventually fulfilled it; this could be seen in the book of Isaiah 40:3.
KJV:The voice of him that crieth in the wilderness, Prepare ye the way of the Lord, make straight in the desert a highway for our God.
The original assignment of John was to prepare the way for Christ; and his baptism of Jesus was also written about Jesus. On the other hand, John was unwilling because he knew Jesus was greater than him but after Jesus explained the necessity and he understood Christ's essence of fulfilling the scriptures, he submitted to baptise Him.
Finally, according to Bro Eli's teaching, it means there are prophecies written about me; I need to search the scriptures and find them so that I might fulfilled them.