Is it permissible to specify a certain number of prayers upon the Prophet (peace and blessings be upon him) on Friday?

Question:
May Allah reward you, Honorable Shaykh. This questioner says: I pray upon the Prophet (peace and blessings be upon him) one hundred times after the Fajr prayer on Friday, and likewise one hundred times after the 'Asr prayer, as I include it with my daily recitation. Is this action valid?

Answer:
Increasing the prayers upon him is required, but specifying a number like one hundred or one thousand requires evidence. Specifying a number requires evidence, whereas increasing the prayers upon him is something the Prophet (peace and blessings be upon him) commanded. Yes.