muqatil bin sulaiman said: "salât (prayer) was established as an obligatory ritual at an early stage of the islamic call, a two rak‘ ah (unit of prayer) salât in the morning and the same in the evening:
"and glorify the praises of your lord in the ‘ashi (i.e. the time period after the mid-noon till sunset) and in the ibkar (i.e. the time period from early morning or sunrise till before mid-noon)." [al-qur'an 40:55]
ibn hijr said: "definitely the prophet [pbuh] used to pray before ‘the night journey’ but it still remains a matter of controversy whether or not the prayer was established as an obligatory ritual before imposing the rules of the usual five prayers a day. it is related that obligatory prayer was established twice a day, in the morning before sunrise and after sunset. it is reported through a chain of narrators that when the prophet [pbuh] received the first revelation, gabriel - the angel, proceeded and taught him how to observe wudu (ablution). when the prophet [pbuh] had finished, he took a handful of water and sprinkled it on his loins. [mukhtasar seerat-ur-rasool p.88]
ibn hisham reported that when it was time for prayers, the messenger of allâh [pbuh] and his companions went into a mountain valley to pray secretly. abu talib once saw the messenger of allâh [pbuh] and ali praying, he asked them what they were up to. when he got to know that it was obligatory prayer, he told them to stay constant in their practice. [ibn hisham 1/247]
this stage of the call, even though conducted in a clandestine manner and on an individual basis, its news leaked out and assumed a public interest all over makkah. in the beginning, the makkan leaders did not care much about muhammad [pbuh]and took no heed of his teachings. at first, they thought that muhammad [pbuh] was merely a religious philosophist like omaiyah bin abi as-salt, quss bin sa‘idah, ‘amr bin nufail and their ilk who used to philosophize on godship and religious obligations. but this attitude of indifference soon changed into real apprehension. the polytheists of quraish began to watch muhammad’s movements closely and anxiously for fear of spreading his call and producing a change in the prevalent mentality. [fiqh as-seerah p.76]
for three underground years of activism, a group of believers emerged stamped by a spirit of fraternity and cooperation with one definite objective in their mind: propagating and deeply establishing the call unto islam. for full three years muhammad [pbuh] had been content to teach within a rather narrow circle. the time had, however, come to preach the faith of the lord openly. the angel gabriel had brought him down a further revelation of allâh’s will to confront his people, invalidate their falsehood and crush down their idolatrous practices.