Hadith 4750
عَنْ أَنَسٍ قَالَ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فِي السُّوقِ فَقَالَ رَجُلٌ: يَا أَبَا الْقَاسِمِ فَالْتَفَتَ إِلَيْهِ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ: إِنَّمَا دَعَوْتُ هَذَا. فَقَالَ النَّبِيُّ صَلَّى الله عَلَيْهِ وَسلم: «سموا باسمي وَلَا تكنوا بكنيتي» . مُتَّفق عَلَيْهِ
Anas (may Allah be pleased with him) narrates: The Prophet (peace and blessings of Allah be upon him) was in the market when a man called out, "Abul Qasim!" When the Prophet (peace and blessings of Allah be upon him) turned towards him, the man said, "I was calling him (someone else)." Then the Prophet (peace and blessings of Allah be upon him) said: "Name yourselves with my name, but do not take my kunyah." Agreed upon.