What is the ruling on masturbation, knowing its prohibition, or being ignorant of it, or doing it unintentionally?

He who commits a forbidden act while knowing it is forbidden and persists in it, his sin and punishment are greater. As for him who commits it out of ignorance of its ruling, we hope he will be excused, but he must learn the matters of his religion and inquire about them. And he who commits it unintentionally or by mistake, there is no sin upon him, for Allah Almighty says: "And there is no blame upon you for that in which you have erred, but [only for] what your hearts intended." However, it is unlikely to commit this abhorrent act unintentionally if one knows its prohibition.