What is the ruling on invoking blessings upon the Prophet, peace and blessings be upon him, with the wording: "O Allah, bless our Master Muhammad an amount equal to the perfection of Allah"?

The people who loved the Prophet, peace and blessings be upon him, and venerated him the most were the Companions. They asked him about how to pray upon him, and he taught them the method mentioned in the Hadith of Ka'b ibn 'Ujrah: "O Allah, send prayers upon Muhammad and upon the family of Muhammad, as You sent prayers upon the family of Ibrahim. Verily, You are Praiseworthy and Glorious. O Allah, send blessings upon Muhammad and upon the family of Muhammad, as You sent blessings upon the family of Ibrahim. Verily, You are Praiseworthy and Glorious."

It is best for a Muslim to follow the predecessors (Salaf) and adhere to what is authentically transmitted in acts of worship. Some scholars have permitted praying with a formula other than the transmitted one, provided it does not contain anything objectionable. However, one must avoid phrases that might suggest that Allah's perfection is quantifiable.

Ibn 'Abidin, in "Radd al-Muhtar," cautioned against the prohibitive dislike (karahah tahrim) of prayers containing phrases such as: "O Allah, send prayers upon Muhammad according to the number of Your knowledge, Your forbearance, the limit of Your mercy, the number of Your words, and the number of Allah's perfection," and similar expressions. This is because they imply the multiplicity of single attributes or the finite nature of the manifestations of knowledge, mercy, and perfection, whereas there is no end to Allah's knowledge, mercy, and perfection.