Where is the part about repenting? I don't think Matthew 7:21 has to do with what your talking about.
repenting is the first step in getting saved - if you sin you have to do it over again
you repented for your past sins not the ones youll do tomorrow
Ezekiel 18
24But when the righteous turneth away from his righteousness, and committeth iniquity,
and doeth according to all the abominations that the wicked
man doeth, shall he live? All his righteousness that he hath done shall not be mentioned: in his trespass that he hath trespassed, and in his sin that he hath sinned, in them shall he die.
25Yet ye say, The way of the Lord is not equal. Hear now, O house of Israel; Is not my way equal? are not your ways unequal?
26When a righteous
man turneth away from his righteousness, and committeth iniquity, and dieth in them; for his iniquity that he hath done shall he die.
27Again, when the wicked
man turneth away from his wickedness that he hath committed, and doeth that which is lawful and right, he shall save his soul alive.
28Because he considereth, and turneth away from all his transgressions that he hath committed, he shall surely live, he shall not die.
29Yet saith the house of Israel, The way of the Lord is not equal. O house of Israel, are not my ways equal? are not your ways unequal?
30Therefore 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.
31Cast 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?
32For I have no pleasure in the death of him that dieth, saith the Lord GOD: wherefore turn
yourselves, and live ye.