Is it permissible to make a covenant with Allah in this form: "I, the servant owned by Allah, the One, the Unique, the Self-Sufficient, I, Mahmoud, affirm that I will abandon unlawful gazes, unlawful touches, and going to anything unlawful as long as I live. O Allah, I swear by You and ask You by Your Greatest Name to make so-and-so, daughter of so-and-so, my wife, my portion, and my destiny"? And what is the sin or expiation for violating it?

It is obligatory for a servant to abandon what Allah has forbidden. The statement "I affirm that I will abandon such and such" does not entail any obligation unless it is uttered with a word indicating commitment, such as "It is due to Allah upon me," or "I vowed to Allah," or "I covenant with Allah." If one covenants with Allah to abandon something or vows to abandon it with a word indicating commitment, then it is safer to offer an expiation for a broken oath (kaffarat yamin (definition)) if they do what they covenanted to abandon, along with the necessity of repentance. An oath and a vow are not contracted merely by writing but by uttering them. Swearing by Allah (i.e., making an oath relying on Allah) is of two types: permissible if it stems from trust in Allah and strength of faith, and forbidden if it stems from arrogance and self-admiration, and it may nullify one's deeds.