The Quran

إِنَّ الَّذينَ يُبايِعونَكَ إِنَّما يُبايِعونَ اللَّهَ يَدُ اللَّهِ فَوقَ أَيديهِم ۚ فَمَن نَكَثَ فَإِنَّما يَنكُثُ عَلىٰ نَفسِهِ ۖ وَمَن أَوفىٰ بِما عاهَدَ عَلَيهُ اللَّهَ فَسَيُؤتيهِ أَجرًا عَظيمًا

Muhammad Asad

Behold, all who pledge their allegiance to thee pledge their allegiance to God: the hand of God is over their hands.¹ Hence, he who breaks his oath, breaks it only to his own hurt; whereas he who remains true to what he has pledged unto God, on him will He bestow a reward supreme.

This refers, in the first instance, to the pledge of faith and allegiance (bay'at ar-ridwan) which the Muslims assembled at Hudaybiyyah gave to the Prophet (see introductory note). Beyond this historical allusion, however, the above sentence implies that as one's faith in God's message-bearer is to all intents and purposes synonymous with a declaration of faith in God Himself, so does one's willingness to obey God necessarily imply a willingness to obey His message-bearer. - The phrase "the hand of God is over their hands" does not merely allude to the hand-clasp with which all of the Prophet's followers affirmed their allegiance to him, but is also a metaphor for His being a witness to their pledge.