What is the expiation for someone who swore on the Qur'an 21 times that he would not drink a certain thing, then broke his oath and drank it each time?

The saying, "By the Lord of this Mus'haf," is objectionable. The Quran is the speech of Allah and His attribute, not a created thing. The Mus'haf contains the Quran between its two covers. The Salaf (pious predecessors) condemned the saying, "O Lord of the Quran," and "Lord of the Mus'haf," if it is intended to mean the Creator of the Quran. However, if the intention behind "Mus'haf" is the papers, covers, and ink, then its meaning is correct, but it should still be avoided due to the ambiguity it carries. Some scholars have been very strict with those who utter this statement.

The aforementioned oath is binding, and what is incumbent upon an oath applies to it. Your truthfulness in it does not exempt it from being a binding oath, but it does remove the sin of swearing it. The swearer may break an oath if breaking it is better, and one single expiation is required for multiple oaths, covering what preceded it, but not what comes after. The expiation for an oath and the ruling on swearing by placing a hand on the Mus'haf can be found in previous fatwas.