Is it permissible for someone to swear by Allah?

Question:
May Allah reward you, Your Eminence the Shaykh. The questioner asks: Is it permissible for someone to swear by Allah, citing the hadith: "Among Allah's servants is one whom, if he were to swear by Allah, He would fulfill his oath"? And may Allah reward you with good.

Answer:
Yes. Swearing by Allah that He will do good is permissible. See the difference: swearing that He will do good is permissible because it is having a good opinion of Allah. But swearing by Allah that He will not do good, or that He will not forgive so-and-so, is not permissible because it is having a bad opinion of Allah the Exalted and despairing of Allah's mercy. So swearing by Allah that He will not do good, or that He will not provide for so-and-so, or that He will not forgive him, is not permissible because it is having a bad opinion of Allah and bad manners with Allah, and it involves despairing of Allah's mercy. As for swearing by Allah that He will do good, this is permissible because it is having a good opinion of Allah the Exalted. Yes, it is good.