This has been talked about before, but the Bible talks about practicing sin.
Mat 7:23; "And then I will declare to them, 'I never knew you; DEPART FROM ME, YOU WHO PRACTICE LAWLESSNESS.'
Rom 1:32; and although they know the ordinance of God, that those who practice such things are worthy of death, they not only do the same, but also give hearty approval to those who practice them.
Rom 2:3; But do you suppose this, O man, when you pass judgment on those who practice such things and do the same yourself, that you will escape the judgment of God?
Gal 5:21; envying, drunkenness, carousing, and things like these, of which I forewarn you, just as I have forewarned you, that those who practice such things will not inherit the kingdom of God.
1Jn 3:10; By this the children of God and the children of the devil are obvious: anyone who does not practice righteousness is not of God, nor the one who does not love his brother.
Gal 5:19 Now the deeds of the flesh are evident, which are: immorality, impurity, sensuality,
Gal 5:20 idolatry, sorcery, enmities, strife, jealousy, outbursts of anger, disputes, dissensions, factions,
Gal 5:21 envying, drunkenness, carousing, and things like these, of which I forewarn you, just as I have forewarned you, that those who practice such things will not inherit the kingdom of God.
If I do something once or twice, I'm not "practicing" it.
If I'm doing something every day... I'm practicing it.
The same goes with repentance. Many people say they have repented, but they are still living in fornication, adultery, pornography, dissipation, and have been been for months, years, even decades after being a Christian.
If you're still doing this things, you haven't repented.
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Jas 2:9; But if you show partiality, you are committing sin and are convicted by the law as transgressors.
Jas 2:10; For whoever keeps the whole law and yet stumbles in one point, he has become guilty of all.
Jas 2:11; For He who said, "DO NOT COMMIT ADULTERY," also said, "DO NOT COMMIT MURDER." Now if you do not commit adultery, but do commit murder, you have become a transgressor of the law.
Jas 2:12; So speak and so act as those who are to be judged by the law of liberty.
Jas 2:13; For judgment will be merciless to one who has shown no mercy; mercy triumphs over judgment.
It says here, that if you break any commandment, you're still just as guilty as if you broke all the commandments.
This is speaking to people who will say something like "I'm a good person". Now matter how good you are, you aren't perfect. You can't be perfect enough for God.
Jesus covers us, Jesus washes us. He makes us perfect. His sacrifice paid for our sins.
... but...
it says int the passage above if we don't show mercy to people, God won't show mercy to us either.
It says in the passage below, if we don't forgive others, God won't forgive us.
Matt 6:14; "For if you forgive others for their transgressions, your heavenly Father will also forgive you.
Matt 6:15; "But if you do not forgive others, then your Father will not forgive your transgressions.
we can still fall short of grace.
Heb 10:26; For if we go on sinning willfully after receiving the knowledge of the truth, there no longer remains a sacrifice for sins,
Tit 1:16; They profess to know God, but by their deeds they deny Him, being detestable and disobedient and worthless for any good deed.