There is this strange idea that the Lord does not incorporate differences, or changes if you will, throughout His timeline for this earth and mankind. In Genesis 2 we read:
Genesis 2:16 And the LORD God commanded the man, saying, Of every tree of the garden thou mayest freely eat:
...except one, of course.
In Genesis 9 we read:
Genesis 9:3 Every moving thing that liveth shall be meat for you; even as the green herb have I given you all things.
The Lord had man start out as vegetarian, and then later made allowance for man to eat anything and everything that lives as meat, along with herbs. Then in Leviticus, the Lord disallowed certain of the animal kingdom that the Jews were not allowed to eat.
So, the Lord has every right to set and change boundaries and limits, even in diet and clothing, as He has demonstrated throughout history. There are many other examples of things the Lord set forth for mankind in general that changed for reasons that we will no into here, but it's interesting that so many will deny the Lord's sovereignty over the salvation of mankind.
In times past, water baptism was necessary for remission of sins, which, one would normally surmise, is indeed a matter of salvation, for without remission of sins, how can one be saved? Peter said nothing about the Blood of Christ, and neither did Christ nor His disciples say anything about the cross to come in all their ministry in the four Gospels when they preached.
When Paul was raised up and shown a mystery shown that was shown, nor even hinted at, by the Lord to no other man until him, water baptism and entrance into Judaism was no longer the means through which Gentiles must enter in order to be saved. Salvation had to start with the Jews, and then to the Gentiles after the fulfillment of the prophecies and Laws that served as types and shadows of Christ, His crucifixion, burial and resurrection on the third day.
Where do these prideful disallowances come from within mankind if not from the desperate wickedness of the heart to say that the Lord could not have set for changes in His plan for salvation for mankind?
Romans 11:25 For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in.
Ephesians 4:17-19
17 This I say therefore, and testify in the Lord, that ye henceforth walk not as other Gentiles walk, in the vanity of their mind,
18 Having the understanding darkened, being alienated from the life of God through the ignorance that is in them, because of the blindness of their heart:
19 Who being past feeling have given themselves over unto lasciviousness, to work all uncleanness with greediness.
The claim of a singular gospel throughout is nothing but willful blindness to the differences of the elements within each gospel. The texts of scripture scream to the reader that we differentiate them in order to see the wondrous way the Lord works. Mankind is shifty and unstable, and thus requires variations in dealings with him...the worldwide flood being a very good case in point.
MM