V.1 John the Baptist is preaching in the wilderness. The fact that John preaches in the wilderness instead of in the temple would tell us that God’s people were in a condition that did not please the Lord, and so John stands in separation from them and calls on them to repent.
V.2 We will find quite often in Matthew’s Gospel the expression “the kingdom of heaven.” This does not mean heaven itself, but as we will find described later on, it refers to the fact that the Lord Jesus had come from heaven and was going to reveal to His people that which He had received from His Father in heaven.
V.6 This baptism is not at all the same as the Christian baptism that we speak of today. This was a baptism unto repentance for the sins of the people and nation of Israel.
V.7-12 John warns those who come to him for baptism that God looks at their hearts.
V.13-17 Jesus comes to John to be baptized, John, of course, is greatly surprised, for he knew that the Lord Jesus had no sins which needed to be repented of. The Lord Jesus knew that the nation of Israel was guilty of many sins — their idolatry of the past, their present self-righteous pride. So to take His place with His nation, He had asked John to baptize Him.
V.16-17 God immediately sets Him apart as being very different from every other one who was being baptized. When the Lord Jesus, came up out of the water, the voice of God is heard from heaven saying “This is My beloved Son, in whom I am well pleased.” The Spirit of God descends like a dove and rests upon the Lord Jesus. Here we find the whole Trinity at the beginning of His public life.