The Ruling on Swearing by the Prayer upon the Prophet

Question:
and blessings be upon him. This is the point of the discussion, for Allah has only commanded us to follow the Messenger (peace and blessings be upon him), and to follow those who followed the Messenger (peace and blessings be upon him). The Salaf followed the Messenger (peace and blessings be upon him). Yes. Regarding the prayer upon the Prophet (peace and blessings be upon him). According to… Chapter? Chapter? If one does not make the mistake, it is forbidden.

Answer:
No, no, no. An oath by prayer—what does that mean? Or does it fall under the statement of the Messenger of Allah (peace and blessings be upon him) regarding swearing by other than Allah? If a person says, "By the prayer, I will not do such and such," or "I will not do so and so," this is not an oath by other than Allah, and it is not an oath in the true sense. It is merely called an oath because it follows the form of an oath. The scholars of jurisprudence called it an oath because it follows the form of an oath. It falls under the verse where Allah the Exalted said to His Prophet: Then He said: So, if you swear, it is a permissible oath that falls under the category of permissible oaths.
And He commanded His Prophet (Glorified and Exalted is He) to expiate for making lawful what is lawful. It was narrated that he (peace and blessings be upon him) forbade honey to himself, or forbade himself something without limit in the bond, because some of his wives were angry with him or complained to him. So the Prophet (peace and blessings be upon him) was angry and forbade honey or the gift to himself. So Allah the Mighty and Majestic rebuked him: Then He said, “Allah has made it lawful for you,” so it became lawful for you. So he performed the expiation for making it lawful, and others, meaning that it is obligatory for him to have an expiation, even though he swore by other than Allah.