This pledge is mentioned in the Holy Quran as follows:

اِنَّ  الَّذِیْنَ یُبَایِعُوْنَکَ  اِنَّمَا یُبَایِعُوْنَ اللّٰہَ ؕ یَدُ اللّٰہِ  فَوْقَ  اَیْدِیْہِمْ ۚ فَمَنْ  نَّکَثَ فَاِنَّمَا یَنْکُثُ عَلٰی

نَفْسِہٖ ۚ وَ مَنْ  اَوْفٰی بِمَا عٰہَدَ عَلَیْہُ اللّٰہَ  فَسَیُؤْتِیْہِ  اَجْرًا عَظِیْمًا (۱۰)

Those who pledge allegiance to you are actually pledging allegiance to Allah. The Hand of Allah is above their hands. So whosoever breaks his pledge only breaks it against himself, but whosoever fulfils his pledge with Allah, He will grant him the supreme reward.^[1]

The hand of the Beloved of Allah became your hand

It is narrated: The form of this pledge was that the noble Prophet صَلَّى الـلّٰـهُ عَلَيْهِ وَاٰلِهٖ وَسَلَّم extended his blessed right hand. All the Companions رَضِیَ اللهُ عَنْهُم  placed their hands on his hand. Then he  صَلَّى الـلّٰـهُ عَلَيْهِ وَاٰلِهٖ وَسَلَّم placed his left hand over everyone else's and said: "This is the hand of ꜤUthmān".^[2]

صَلُّوۡا عَلَى الۡحَبِيۡب                                                صَلَّى اللّٰهُ عَلٰى مُحَمَّد

O devotees of the Messenger! During the BayꜤah al-Riḍwān, when Sayyidunā ꜤUthmān رَضِىَ اللّٰهُ عَـنْهُ  was in Makkah Mukarramah, several faith-inspiring events took place.

Let us hear two of these narrations:

Sayyidunā ꜤUthmān رَضِىَ اللّٰهُ عَـنْهُ  and his Love for the Sunnah of Mustafa!