Was it obligatory for the Arabs, before the advent of Prophet Muhammad, peace be upon him, to follow the religion of Ishmael, peace be upon him, and how does this reconcile with His Almighty's saying: "But as a mercy from your Lord, to warn a people to whom no warner had come before you, that they might remember" (Al-Qasas 46)?

Ishmael (peace be upon him) was a prophet and messenger to the Arabs in Mecca and its surroundings, calling them to the religion of monotheism. However, with the passage of time, they forgot this religion, and little of it remained. The people to whom no warner came in the noble verse are Quraish and those around them, and it does not refer to all Arabs, as Hud, Salih, Shu'ayb, and others were sent to them.