What is the ruling on one who made a covenant with Allah to abandon an action, but then committed it?

If you have made a covenant with Allah the Almighty concerning a matter, you must fulfill it, as Allah the Almighty says: (And fulfill the covenant of Allah when you have covenanted, and do not break oaths after their confirmation while you have made Allah your guarantor). So, if you break the covenant, you must repent and offer an expiation for breaking an oath, which is feeding ten poor persons, or clothing them, or freeing a slave. If you are unable to do that, then fasting for three days.