What is the ruling on one who commits a sin intending to repent after doing so, such as someone who commits a sin then intends to repent later, just as the brothers of Yusuf did when they threw him into the well and intended to repent after completing their crime?

A Muslim does not know when he will die, and it is his duty to remember death, do good deeds, and avoid procrastination in repentance. It is true that repentance erases what came before it, but this does not justify committing sins. Who can guarantee remaining alive long enough to repent? The questioner's deduction from the actions of Yusuf's brothers, when they said: "Kill Yusuf or cast him forth to some [other] land; the attention of your father will be exclusively for you, and you will be, after that, a righteous people," is wrong from two perspectives: First, their action was a mistake, and they admitted it, so there is no need to imitate them. Second, the law of those before us is not to be adopted if it contradicts our law, and there is nothing in our law that permits committing a sin with the intention of repenting from it.