Prayer: This English word serves to translate three different concepts in Islam, namely du'a, salah and dhikr.
Du'a (lit. "calling") is an "individual" or spontaneous prayer in which the worshiper expresses his personal sentiments and petitions God. A special form of du'a is the Ya Latif prayer which is used in moments of distress, or in cases of grave illness.
Salah (lit. "worship" from an Aramaic word whose root meaning is "to hallow") is the "canonical" or "ritual" prayer which must be performed at five appointed times each day. The basic unit is the rak'ah (a round of ritual actions and sacred phrases), so that each canonical prayer consists of a prescribed number of raka'at (pl. of rak'ah). Superogatory raka at are permitted and, indeed, encouraged. Conversely, if for any valid reason it is not possible to pray the canonical prayers at the appointed time, they are to be made up afterwards. The form and contents of the salah are fixed by the Sunnah, the Prophet's example, and by the traditions of the Schools of Law.
Salah is an act of worship, a religious service, special forms of which are prescribed for the occasions of death, religious festivals, and solar eclipses, or to ask for guidance in particular circumstances (istikharah), or to pray God for rain (istisqa).
The third category of prayer is the inward prayer of "remembrance" of God, invocation, dhikr.
Prayers on the Prophet (Ar as-salah 'ala-n-Nabi). The word salah, which denotesthe ritual prayer of Islam, and its verb salla, "to praise," "to bless," often translated as "to pray upon," appears to originate from Aramaic the root meaning being "to hallow"). The Quran says: "Verily, God and his Angels send blessings upon the Prophet. You who believe, call blessings upon him and peace," (33:56).
Muslims use a number of such invocatory prayers in various rituals and ceremonies. The du'a (petitioning prayer), which follows the salah (ritual, or canonic prayer), is always introduced with a prayer on the Prophet (PBUH). This is one version used in North Africa:
As-salatu wa-s-salamu 'alayka ya Nabiyya 'Llah, as-salatu wa-s-salamu Alayka ya Habiba-Llah, as-salatu wa-s-salamu alayka ya Rasula-Llah; alfu salatin wa alfu salamin 'alayka wa ala alik wa rrida'u 'anashabika, ya khayra mani 'khatara "Llah.
Blessing and peace be upon you, O Prophet of God;
Blessing and peace be upon you O Messenger of God.
Thousandfold blessing and thousanfold peace upon you and upon your people, and God's felicity upon your companion, O best of the chosen of God.
Allahumma salli 'ala Sayyidina, Muhammadin 'adada khalqika wa rida'i nafsika wa madadi kalimatik.
Subbhana Llahi 'amma yasifun, wa salamun 'ala-i-mursalin, wa-I-hamduli-Llahi Rabbi-I- alamin.
Our Lord, bless our master Muhammad as much as the number of your creations, the felicity of your essence, and the ink necessary to write your words. Magnified be God above what is attributed to Him, and peace upon the Messengers, and Praise to God, the Lord of the worlds.
When a believer mentions the Prophet (PBUH) - and he is rarely mentioned by name, but rather by the title Prophet (Nabi), or Messenger of God (Rasulu-Llah) - it is customary to add: sallaLlahu 'alayhi wa sallam ("May God bless him and give him peace").. The "blessings" (salah) refer to "vertical" graces descending into the soul and "peace" (salam) to a "horizontal" grace of inward dilation which receiveds and stabilizes those blessings.