Imam Haskafi mentions in his Durr al-Mukhtar concerning sending the peace and blessings on the prophet (Allah bless him and give him peace),
“It is obligatory once in a persons life, without any difference of opinion…and it is differed upon concerning it's necessity every time he is mentioned (Allah bless him and give him peace) the chosen opinion according to Tahawi is that it is necessary (wajib) every time he is mentioned and the opinion of the school is that is repreating it is recommended [f: that is, saying it once in a session is necessary, and repeating it every time the Prophet’s name is mentioned is recommended].”
Ibn Abidin explains,
“Sending of blessings on the prophet (Allah bless him and give him peace) is necessary once in each session [where his name is mentioned]...and its repetition is recommended [if the Prophet’s name (Allah bless him and give him peace) is repeated].” [Radd al-Muhtar `ala al-Durr al-Mukhtar, 1:246, Bulaq ed.]
This was taken from the position verified by Imam Abu’l Barakat al-Nasafi in his al-Kafi and Imam Kamal ibn al-Humam in his Zad al-Faqir.
Places and time when the sending of peace and blessings on the Prophet (Allah bless him and give him peace) is recommended
Imam al-Haskafi mentions,
“It is recommended in all times, when possible.”
Ibn 'Abidin adds,
“The scholars have specifically mentioned a number of places when it is recommended:
· on Fridays during the day and the night before, in the morning and evening,
· upon entering the mosque and upon exiting,
· when visiting his blessed grave (Allah bless him and give him peace),
· when at Safa and Marwa,
· during the Friday sermon and other sermons [f: the the khatib; as for those listening, they do not do so with their tongues, but within themselves],
· after replying to the adhan,
· when the call to commence the prayer is given (iqamah),
· in the beginning, middle and end of a supplication (du`a) [f: because the salat on the Prophet (Allah bless him and give him peace) is accepted by Allah, and He will not reject that which is between it, out of His supreme generosity, as the scholars mention],
· after the du'a of qunut [in the witr prayer],
· when meeting and parting,
· during the ablution,
· when having forgotten something,
· when giving an admonition,
· when commencing and completing the reading of hadith,
· for all authors, students, and teachers,
· people getting married and people marrying others off,
· in letters,
· and before all important matters.” [Radd al-Muhtar, 1:348, Bulaq]
What is the reward and benefit of the peace and blessings?
Imam al-Sakhawi records numerous benefits and rewards of sending blessings on the blessed prophet (Allah bless him and give him peace). These include:
1. Allah's sending blessings on the slave
Abu Huraira (Allah be pleased with him) relates that the Prophet (Allah bless him and give him peace) said, “He who sends blessings on me once, Allah sends him blessings ten times.” [Muslim, Abu Dawud, & Tirmidhi]
Anas ibn Malik (Allah be pleased with him) relates that the Prophet (Allah bless him and give him peace) said, “He who sends blessings on me once Allah sends blessings on him ten times and removes from him ten sins and raises him by ten degrees.” [al-Nasa'i].