This very common phrase (AL-SALAT ALA AL-NABI and AL-TASLEEM) derives from the following verse:
"God and His angels ‘Yossalloon ala al Nabi’, O you believers you shall ‘Salloo alayhee’ and ‘Sallemoo tasleema’." (33/56)
Since this is a clear command from God, we must surely obey it. However, and before obeying this command we must first understand the meaning of it. We notice that the verse contained two commands, the ‘Salla ala al Nabi’ and the ‘Tasleem’.
First we should inspect the present interpretation of these words among Muslims today, then we must find out whether this interpretation is in line with the one contained in the Quran. To do this, the easiest method is to ask any Muslim as to what is the meaning of the simple and widely spoken words ‘Salli ala al Nabi’.