What is the ruling in Islam regarding one who does not acknowledge religion and denies kindness after Allah has relieved him? And what are the conditions for repentance?

Whoever denies a debt he owes to another while knowing of it, has committed a grave sin by consuming people's wealth unjustly. He must return the right to its owner, for the recompense for a loan is praise and repayment. And whoever seizes a Muslim's right by his oath, Allah has ordained for him the Fire and forbidden for him Paradise. And whoever takes people's wealth intending to destroy it, Allah will destroy him. And whoever seizes a Muslim's property unjustly will meet Allah while He is angry with him. And let him who has wronged his brother seek his absolution. The matter becomes more severe if he is made to swear an oath and he swears falsely, for whoever swears a false oath to seize thereby the property of a Muslim, Allah will not speak to him on the Day of Resurrection, nor will He look at him.