Repentance is hard for us moderns to understand - and in fact repentance is typically "grossly" misunderstood.
What happens is that repentance - which is primarily between one person and God - gets mixed up with emotions such as regret, and more-or-less well-meaning and perhaps helpful "inter-human" (or 'social') actions such as apology and restitution.
I would say that:
REPENTANCE IS THE ACKNOWLEDGEMENT THAT I "HAVE" SINNED; WHICH INCLUDES UNDERSTANDING THAT WHAT I HAVE DONE IS INDEED A SIN; AND THE ASKING OF GOD'S FORGIVENESS FOR MY SINS WITH A CONTRITE AND SORROWFUL HEART.
In the above circumstances, this forgiveness will "always" be forthcoming.
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WHAT REPENTANCE IS NOT includes the emotion of "regret" for what I have done, focused on "wishing I had not done it"; nor is it to "apologize" to someone for what I have done - nor is it to ask another "person" to "forgive me" - nor is repentance about trying to undo what I have done, to set things right or repair the damage, nor is it to striving to make amends for what I have done.
All these may be (and often are) "good things to do in and of themselves", but they are NOT REPENTANCE.
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Repentance is essentially between myself and God; and God's forgiveness is a washing-clean, to allow a fresh start - but a "spiritual" fresh start; and not a fresh start in this-worldly matters, because" - sin can never be undone. "
God cannot ever make it as if there never had been sin.
But what God can and does do - what repentance can and does do - is to "heal" us from the effects of sin.
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Origin: master-of-pentagram.blogspot.com