It is WHEN the Lord returns that He will blot out THEIR SINS AS A NATION .
No.
Deu 30:2 And shalt return unto the LORD thy God, and shalt obey his voice according to all that I command thee this day, thou and thy children, with all thine heart, and with all thy soul;
Deu 30:3
That then the LORD thy God will turn thy captivity, and have compassion upon thee, and will return and gather thee from all the nations, whither the LORD thy God hath scattered thee.
Rev 22:11 He that is unjust,
let him be unjust still: and he which is filthy,
let him be filthy still: and he that is righteous,
let him be righteous still: and he that is holy,
let him be holy still. Rev 22:12 And, behold, I come quickly; and my reward is with me, to give every man according as his work shall be.
The fountain was opened up 2000 years ago---
Zec 13:1 In that day there shall be a fountain opened to the house of David and to the inhabitants of Jerusalem for sin and for uncleanness.
and this began to occur on the day of Pentecost--
Zec 12:10 And I will pour upon the house of David, and upon the inhabitants of Jerusalem, the spirit of grace and of supplications: and they shall look upon me whom they have pierced, and they shall mourn for him, as one mourneth for his only son, and shall be in bitterness for him, as one that is in bitterness for his firstborn.
Zec 12:11 In that day shall there be a great mourning in Jerusalem, as the mourning of Hadadrimmon in the valley of Megiddon.
Zec 12:12 And the land shall mourn, every family apart; the family of the house of David apart, and their wives apart; the family of the house of Nathan apart, and their wives apart;
Zec 12:13 The family of the house of Levi apart, and their wives apart; the family of Shimei apart, and their wives apart;
Zec 12:14 All the families that remain, every family apart, and their wives apart.
as per--
Act 2:36 Therefore let all the house of Israel know assuredly, that God hath made that same Jesus, whom ye have crucified, both Lord and Christ.
Act 2:37 Now when they heard this, they were pricked in their heart, and said unto Peter and to the rest of the apostles, Men and brethren, what shall we do?