With regard to sins, the Messengers, including Muhammad (peace and blessings of Allah be upon him), never committed any sin intentionally as an act of disobedience towards Allah after receiving their Mission. Before the Prophets were given their Mission, the scholars have said that it is possible that they may have committed some minor sins, but they were protected from committing major sins such as Zina, drinking wine, etc. But after they received their Mission, the correct view is that they may have committed some minor mistakes but this was not approved of and they were rebuked.