(1) The Israelites coming to John for baptism had no idea of a New Covenant. They were coming to identify with the coming Messiah he preached,
a Messiah of the Old Covenant.
Au contraire, John's message and preparatory message baptism was not merely a rehash of the OT law and prophets. In fact, after the initial proclamation it was accompanied by the
PERSONAL APPEARANCE OF THE
MESSIAH HIMSELF. WHO OFFERED HIMSELF AS THE PROMISE OF REDEMPTION.
(2) The offer was made to all people: 'as it has been written in the book of the words of Isaiah the prophet, saying: “The voice of one shouting in the wilderness: ‘Prepare the way of the Lord; make straight His paths. 5 Every valley will be filled and every mountain and hill will be made low; the crooked will be made straight, and the rough into smooth paths; 6 and
ALL FLESH will see the salvation of God.
(3) He had not come to renew the Mosaic covenant but to make a
NEW COVENANT that could save anyone even all the nations:
31 “Behold, the days are coming, says the Lord, when I will make a new covenant with the house of Israel and with the house of Judah— 32
not according to the covenant that I made with their fathers in the day that I took them by the hand to lead them out of the land of Egypt, My covenant which
they broke, [
a]though I was a husband to them, says the Lord. 33 But this
is the covenant that I will make with the house of Israel after those days, says the Lord:
I will put My law in their minds, and
write it on their hearts; and
I will be their God, and they shall be My people. 34 No more shall every man teach his neighbor, and every man his brother, saying, ‘Know the Lord,’ f
or they all shall know Me, from the least of them to the greatest of them, says the Lord.
For I will forgive their iniquity, and their sin I will remember no more.”
Jeremiah 31:31-34)