Looking at the differences in salat is interesting yet confusing. Some say the movements for men and women are slightly different, others say they are exactly the same. Some practice qabd and others sadl. Some put their hands at the chest but others at the navel.
The people at the time of our 4 great imams were living amongst Sahaba, Tabiin, and Taba Tabiin. How could the observers of the Prophet (saws) and Sahaba, after seeing them pray so many times, still have such differences with salat, even to the extent of which some Malikis make it makrooh to pray qabd? It doesn’t seem to make sense that there would be such vast witnessing and practical differences in such a short time after the Prophet (saws) died, specifically on a religious ritual performed multiple times a day and often in public. What explains this?
The differences were already present in the Prophet’s practice itself, not only after he died; and they are less “vast” than you suggest. Even so, no single observer witnessed every Salat ever prayed by the Prophet (upon him blessings and peace); but the collective witnessing shows that he himself gave alternatives and choices in certain details.
The science of khilaf (divergence) is an Islamic discipline in its own right, requiring knowledge of Law, Hadith and history. That science is firmly based on the principle, taught by the early Imams of Fiqh, that “Differences in the Umma are a mercy.” Studying those differences with qualified teachers, pondering that mercy and availing ourselves of it is part of our Religion.
Hajj Gibril Haddad