Is it permissible to invoke blessings upon the Prophet (peace be upon him), glorify Allah, seek His forgiveness, and engage in remembrance using the phrasing: "to an infinite number to infinity," with the aim of multiplying the reward, by analogy with the hadiths that mention the virtue of multiplied remembrance?

First: The ruling on using the phrase "O Allah, send blessings upon our Master Muhammad an infinite number of times."

There is no objection to sending blessings upon the Prophet, peace be upon him, with this wording, and much reward is hoped for. However, it is better to follow the transmitted forms, such as saying: "O Allah, send blessings upon Muhammad as many times as You have created," based on the hadith (definition) of Abu Umamah and Juwairiyah. Al-Hafiz Ibn Hajar transmitted the permissibility of wordings that imply the multiplication of remembrance.

Second: The best forms of sending blessings upon the Prophet ﷺ is the Ibrahimiyyah prayer.

The best forms of sending blessings upon the Prophet, peace be upon him, are those he taught to his Companions, which is the Ibrahimiyyah prayer, due to his saying, peace be upon him, when asked: "How should we send blessings upon you?" He replied: "Say: 'O Allah, send blessings upon Muhammad and upon the family of Muhammad...'" as narrated by Al-Bukhari and Muslim.