As mentioned earlier, the rite of water baptism served to "make ready a people prepared for the Lord " so that they "might serve Him...in holiness and righteousness " (Lk.1:17,74,75).
The children of Israel could not serve The Lord Jesus in righteousness and holiness as long as they remained living a life that defiled them. Therefore, they were to "repent" (have a change of mind) in regard to the sinful lifestyle they were living.
Let us look at Peter's words on the day of Pentecost in regard to the rite of water baptism:
""Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Spirit" (Acts 2:38).
This baptism was only for those who had already believed (Acts 8:36-37) and were already saved. Therefore, the remission of sins in this instance was not for salvation but intead for "fellowship" with the Lord:
In the Journal of the Grace Evangelical Society David R. Anderson writes: "We are suggesting that John the Baptist, Jesus, and Peter had dual ministries. One was to call the nation of Israel back into fellowship with Yahweh. The covenant relationship had long since been established. The nation of Israel did not need a new relationship with God. But they were sorely lacking in fellowship...John the Baptist, Jesus, and Peter were all trying to persuade Israel to repentance and turning that would bring them back to a refreshing fellowship with God...Now as a nation they needed to repent and turn (Acts 3:19) in order to have fellowship with God" [emphasis added] (Anderson, "The National Repentance of Israel," Journal of the Grace Evangelical Society, Autumn 1998, Volume 11:21).
The baptism of Acts 2:38 was for the purpose of cleansing those who were already saved to bring them back to "fellowship" with the Lord. It served the same purpose as the "confession" of sin which the Apostle John speaks of here:
"This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth...If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness" (1 Jn.1:5-6, 9).
Here John is saying that if we "confess" our sins then we will be cleansed from the things which interrupt our "fellowship" with God. The baptism of repentance was also in regard to confessing sins:
"In those days came John the Baptist, preaching in the wilderness of Judaea, And saying, Repent ye: for the kingdom of heaven is at hand...Then went out to him Jerusalem, and all Judaea, and all the region round about Jordan, And were baptized of him in Jordan, confessing their sins" (Mt.3:1-2,5-6).
All Christians receive the forgiveness of sins when they believe:
"To him give all the prophets witness, that through his name whosoever believeth in him shall receive remission of sins" (Acts 10:43).
When a person believes he is baptized into the body of Christ by one Spirit and are created in "righteousness and true holiness" (Eph.4:24).
That refers to a Christian's "position" in Christ but our "walk" is another matter. In our "walk" sin separates us from our fellowship with God:
" But your iniquities have separated between you and your God, and your sins have hid his face from you, that he will not hear" (Isa.59:2).
Being in "fellowship" with the Lord is the same things as "abiding" in Him. The Lord Jesus said that a believer cannot "bear fruit" or effectively serve Him unless he abides in Him:
"Abide in Me, and I in you. As the branch cannot bear fruit of itself, except it abide in the vine; no more can ye, except ye abide in me. I am the vine, ye are the branches: He that abideth in me, and I in him, the same bringeth forth much fruit: for without me ye can do nothing" (Jn.15:4-5).
In order to be a "people prepared for the Lord" so that they might serve Him in holiness those already saved were to submit to the rite of water baptism.
Today we cannot serve the Lord except we be clean from all of our sins:
"I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service" (Ro.12:1).