Muhammad (S), right from his childhood was known for his virtue and lofty conduct and was far removed from the prevalent vices of the day like idolatry, dishonesty, drinking, gambling, cowardice etc., which were the hallmarks of the Makkan society. His noble character stood him out as the most impeccable one ever, to the point that his people called him 'as-Sadiq' (the Truthful) and 'al-Amin' (the Honest). They put their complete trust in him and always turned to him as an impartial judge in their frequent disputes.
He was a born believer whose heart was free from the filth of disbelief and polytheism. Never had the boy been near idols let alone worship them. The All-Knowing Allah, Who had singled out the child for the greatest task and blessings that lay ahead, had inspired Muhammad's (S) young heart with His Greatness, Power and Majesty.
His pristine purity was indicative of his future greatness, for how could people believe in him and put their trust in him if they see him prostrating before manmade objects and indulging in vices like any ordinary Arab of the day.
Surely, none would have responded to his call to Islam, towards virtue and towards deliverance from oppression, and none would have believed him if they were not sure of vouchsafing his truthfulness and honesty.
Thus Divine providence was at work, right from the beginning in his case, grooming, inspiring and educating the young Muhammad (S) and finally introducing him as a model of emulation and messenger for all of mankind.