with an extra prophet, god didnt change, nature of worship did. They did start with an interesting premise, that there is a full stop, this way until the messiah, messiach, 13th mullah etc shows up, other folks leave room for more direction
lets use a christian saying to describe muslims shall we
dont judge christ by the christians
works the same way for the muslims
no being can tell you what to do or not do, its a free will thingy