From the Islamic perspective the "uncertainty" elements is like the Hadith that you can have faith in Allah AND tie the camel instead of just having faith the camel won't run away.
Pure faith based beliefs like believe God will save them instead of taking medicine and going to the doctor is more of American evangelical Christianity
Mohammed, like Moses, fought actual battles and thus dealt with uncertainty his whole life. The abrogation paths of the Koran delt with uncertainty and rules changed depends on the situation.
Mohammed acted a lot more like a prophet of the old testament than the "ideal Muslim"