Sahih Muslim 2131
Sahih Muslim · Book 38: The Book of Manners and Etiquette · The Prohibition Of Taking The Kunyah Abul-Qasim, And The Names Which Are Recommended
Anas reported that person at Baqi' called another person as" Abu'l- Qasim," and Allah's Messenger (ﷺ) turned towards him. He (the person who had uttered these words) said:
حَدَّثَنِي أَبُو كُرَيْبٍ، مُحَمَّدُ بْنُ الْعَلاَءِ وَابْنُ أَبِي عُمَرَ - قَالَ أَبُو كُرَيْبٍ أَخْبَرَنَا وَقَالَ، ابْنُ أَبِي عُمَرَ حَدَّثَنَا وَاللَّفْظُ، لَهُ - قَالاَ حَدَّثَنَا مَرْوَانُ، - يَعْنِيَانِ الْفَزَارِيَّ - عَنْ حُمَيْدٍ ، عَنْ أَنَسٍ ، قَالَ نَادَى رَجُلٌ رَجُلاً بِالْبَقِيعِ يَا أَبَا الْقَاسِمِ . فَالْتَفَتَ إِلَيْهِ رَسُولُ اللَّهِ صلى الله عليه وسلم . فَقَالَ يَا رَسُولَ اللَّهِ إِنِّي لَمْ أَعْنِكَ إِنَّمَا دَعَوْتُ فُلاَنًا . فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " تَسَمَّوْا بِاسْمِي وَلاَ تَكَنَّوْا بِكُنْيَتِي " .
Messenger of Allah, I did not mean you, but I called such and such (person), whereupon Allah's Messenger (ﷺ) said: You may call yourself by my name, but not by my kunya.