Another indispensable characteristic of the Prophets is sincerity. Sincerity is purity of intention – to do everything solely for the sake of God. We are all ordered to worship God sincerely, as declared in the Qur’an:

They were commanded only to serve God, making the religion His sincerely, men of pure faith, and to perform the prayer, and pay the alms. (al-Bayyinah, 98.5)

God mentions sincerity as the foremost attribute of the Prophets. He says of Moses:

And mention in the Book Moses; he was made sincere, and he was a Messenger, a Prophet. (Maryam, 19.51)

God chose all the Prophets, purified them and made them sincere to the utmost degree.

We worship God only because we are His slaves and He has commanded us to worship Him. By worshipping Him, we secure His approval and get the reward of our worship in the Hereafter. The greatest thinker of our century, Said Nursi, said in this respect:

Do what you do only for God’s sake; start for God’s sake; work for God’s sake and act within the sphere of God’s good pleasure.

God’s Last Prophet, upon him be peace and blessings, was also the foremost in sincere worship of God, so that a day would come when someone said of him: ‘No one can remain as humble as he was at the beginning of his career or quest after attaining its height. Muhammad was an exception to this.’ He is so great, so sublime that we still stand in respect for him, although he used to warn his Companions, saying, Do not stand up when I come upon you as the Persians do (for their elders). Although his Companions respected him to the utmost degree, he deemed himself a poor slave of God. On the day when he conquered Makka, he was not different at all from the day when he humbly began his mission. At the outset of his mission, he would sit and eat with the poor and slaves. As he entered Makka as a victorious commander, he rode a mule in so deep submission and humility before God that he bent forward with his forehead touching the packsaddle of the beast. He was prostrating himself before God and taking refuge in Him from being a tyrannical, haughty conqueror.

God’s Messenger, upon him be peace and blessings, had a single intention, namely, to please God and worship Him sincerely. He had to worship, and in fact did worship, Him at the level of perfect goodness and utmost sincerity, as he himself stated in a famous Tradition:

Perfect goodness is to worship God as if you were seeing Him, and while you see Him not, yet truly he sees you.

The Prophet lived every second of his life in complete consciousness of being supervised by God.