Without repentance there is no forgivenessYeah, but they weren't believers when He purged their sins. Their believing had nothing to do with the the work He did and sat down at the Right hand of God. Some who He did that for were not even born yet.
Acts 3:19 Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord;
1 John 1:9 If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.
Acts 2:38 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 Ghost.
Luke 24:47 And that repentance and remission of sins should be preached in his name among all nations, beginning at Jerusalem.
2 Chron 7:14 If my people, which are called by my name, shall humble themselves, and pray, and seek my face, and turn from their wicked ways; then will I hear from heaven, and will forgive their sin, and will heal their land.
Prov 28:13 He that covereth his sins shall not prosper: But whoso confesseth and forsaketh them shall have mercy.
Acts 17:30 And the times of this ignorance God winked at; but now commandeth all men every where to repent:
Mark 1:15 And saying, The time is fulfilled, and the kingdom of God is at hand: repent ye, and believe the gospel.
Ezek 18:30–32 Therefore I will judge you, O house of Israel, every one according to his ways, saith the Lord God. Repent, and turn yourselves from all your transgressions; so iniquity shall not be your ruin. Cast away from you all your transgressions, whereby ye have transgressed; and make you a new heart and a new spirit: for why will ye die, O house of Israel? For I have no pleasure in the death of him that dieth, saith the Lord God: wherefore turn yourselves, and live ye.
Isa 55:7 Let the wicked forsake his way, And the unrighteous man his thoughts: And let him return unto the Lord, and he will have mercy upon him; And to our God, for he will abundantly pardon.
Luke 13:3 I tell you, Nay: but, except ye repent, ye shall all likewise perish.
Acts 26:20 But shewed first unto them of Damascus, and at Jerusalem, and throughout all the coasts of Judaea, and then to the Gentiles, that they should repent and turn to God, and do works meet for repentance.