What is the ruling of the Sharia regarding one who broke his oath sworn upon the Noble Qur'an not to return to committing a forbidden act, and then regretted it, and what expiation is due upon him?

What is incumbent upon one who breaks his oath and falls into something forbidden is to seek Allah's forgiveness (Istighfar) and repent. He also owes an expiation for breaking an oath (kaffarat yamin). The expiation for breaking an oath is to feed ten poor persons, or to clothe them, or to free a slave. If he cannot find any of these, then he must fast for three days.