What is the ruling on one who has repeatedly sworn by Allah falsely, then confessed the truth and sworn to it upon the Book of Allah, and what is the expiation for that, and how is one to repent from it?

Swearing falsely by Allah (al-Yamin al-Ghamus) is one of the major sins. Whoever commits it must hasten to sincere repentance, which is sufficient according to the majority of scholars. The Shafi’is hold that expiation for an oath (kaffarat yamin) is obligatory along with repentance. This expiation is feeding ten poor people, or clothing them, or freeing a slave. If one cannot find any of these, then fasting for three days. This is more cautious. Repentance consists of regretting the sin, abandoning it, resolving not to return to it, and restoring any injustices.