What is the manner of sending blessings upon the Prophet (peace be upon him)? And is it permissible to send blessings upon him with the formulas: "O Allah, bless Muhammad as much as the number of Your creation, the pleasure of Your Self, the weight of Your Throne, and the ink of Your words," and "O Allah, bless Muhammad filling the heavens and the earth"?

It is permissible to say the phrase "filling the heavens and the earth, and filling whatever else You wish thereafter" when invoking blessings upon the Prophet (peace be upon him), despite its mention in the noble Hadith (definition) concerning the praise of Allah Almighty. However, it is better and more complete to adhere to the authentic forms of invoking blessings upon the Prophet (peace be upon him) that have been transmitted from him.