Some of the fuqaha’ stated that there are seventeen verbal Sunnahs in prayer, and fifty-five actions which are Sunnah.
The prayer is not invalidated if one omits one of these actions, even if that is done deliberately, unlike the pillars and obligatory parts.
The Sunnah words of the prayer, of which there are eleven, as follows:
(i) Saying after the opening takbeer, “Subhaanaka Allaahumma wa bi hamdika, wa tabaaraka ismuka, wa ta’aala jadduka wa laa ilaaha ghayruka(Glory and praise be to You, O Allaah; blessed be Your name, exalted be Your Majesty, and there is no god but You).” This is called du’aa’ al-istiftaah (opening du’aa’)
(ii) Seeking refuge with Allaah
(iii) Saying Bismillaah
(iv) Saying Ameen
(v) Reciting a soorah after al-Faatihah
(vi) Reciting out loud, in the case of the imam
(vii) Saying after the tahmeed (Rabbana wa laka’l-hamd), for one who is not praying behind an imam: “Mil’ al-samawaati wa mil’ al-ard wa mil’ ma shi’ta min shay’in ba’d (Filling the heavens, filling the earth, and filling whatever else You wish).” (The correct view is that it is also Sunnah for one who is praying in congregation)
(viii) Saying the tasbeeh when bowing more than once, such as a second or third time or more
(ix) Saying the tasbeeh in prostration more than once
(x) Saying “Rabb ighfir li (Lord forgive me)” more than once between the two prostrations
(xi) Sending prayers upon the family of the Prophet (peace and blessings of Allaah be upon him) in the last tashahhud and sending blessings upon him and upon them, and saying du’aa’ after that.