We would like to point out from the very beginning that this is a very minor issue and Muslims should not allow Satan to divide them on such a small point. While there is evidence that it is preferable to place the knees down first, either way of prostrating is acceptable. No doubt, some people prefer one way or another because of problems with their back or knees.
Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states: “Whether one should place knees or hands first while kneeling down to make sujud (prostration) is definitely not one of the integrals of Salah (ritual Prayer), for, according to all scholars, Salah is deemed as valid regardless of whether one places knees or hands first on the ground.
Scholars have been divided on this issue. One group considers it preferable to place the knees first, while another insists on placing hands first while prostrating. The former view (that is, placing knees before the hands) is the preferred view of the majority of imams and scholars of fiqh and Hadith belonging to all of the schools of jurisprudence, while the latter view is adopted by a minority of scholars.
the divergence of views among scholars on this issue can be traced to their different approaches in reconciling the various reports from the Prophet (peace and blessings be upon him) that are seemingly contradictory. For instance, according to a report from Wa’il ibn Hujur, the Prophet (peace and blessings be upon him) was in the habit of placing his knees before his hands while prostrating. Contrary to this, a report from Abu Hurayrah implies that the Prophet (peace and blessings be upon him) allegedly forbade the practice of placing knees before hands.
Upon a closer scrutiny of all the available reports in this regard, some scholars have concluded that the first view is the most preferred and authentic. Their reasons are that the report of Wa’il is more authentic and is also supported by other traditions, while Abu Hurayrah’s report seems to be flawed, for its first part seemingly contradicts the second. It specifically states that the Prophet forbade us copying the behavior of camels while kneeling down; now it is evident the camels place their forelegs before their hind legs while kneeling down.
Based on above mentioned considerations, most scholars have acted on the conclusive evidence of the report of Wa’il ibn Hujur. Accordingly, they consider it preferable to place the knees before hands while prostrating.
Having said this, however, let me add: We must not rush to invalidate the Prayers of those who follow the other view (that is, placing hands before the knees). If it had been an absolute requirement of
Salah, then we would not have faced such ambiguity on this issue in the first place. For it is only reasonable to conclude that if it had been the case, the Prophet (peace and blessings be upon him) would have taught the same in no uncertain terms, just as he taught us about other integrals of Salah.”