Repentance

Christian Alexander said:

What is its point of origin? 

That would be its etymology, right? This is where Barr arrives (from Semantics):

"It is perhaps worth noticing in passing that a similar argument could be produced from Hebr. n-ḥ-m, which is ‘comfort’ in the piʿel and ‘repent’ in the niphʿal. The relation between these two senses can be fitted into the theological structure of Christianity just as well as that between the senses of παραμυθέομαι. Such an argument is just as totally valueless as the one from the Greek word."

But I thought you'd enjoy a snippet from Hermas 7 (Hermeneia).  The english 'convert' is the greek 'repent'.  Notice the closeness in concepts.

“Thus the noble angel gave directives about you. He wants you to be tried.” “What evil have I done, sir,” I said, “to be handed over to this angel?” “Listen,” he said, “your sins are many, but not so many that you should be handed over to this angel. But your household have committed great sin and lawlessness; the noble angel has become fed up with their deeds, and for this reason commanded that you be afflicted for a time, so that they will be converted and purify themselves from every desire of this world.

When they are converted and purified, the angel of punishment will leave you.”