Sahl said, "Al-Mundhir ibn Abi Usayd was brought to the Prophet ﷺ when he was born and the Prophet placed him on his thigh while Abu Usayd was seated near him. The Prophet ﷺ was busy with something in front of him, so Abu Usayd told someone to take his son from the Prophet's leg. When the Prophet ﷺ became aware of it, he asked, 'Where is the child?' Abu Usayd replied, 'We sent him home.' The Prophet asked, 'What is his name?' He replied, 'Such-and-such.' The Prophet said, 'No, rather his name is al-Mundhir.' So we called him al-Mundhir from that day."

حَدَّثَنَا سَعِيدُ بْنُ أَبِي مَرْيَمَ، قَالَ: حَدَّثَنَا أَبُو غَسَّانَ قَالَ: حَدَّثَنِي أَبُو حَازِمٍ، عَنْ سَهْلٍ قَالَ: أُتِيَ بِالْمُنْذِرِ بْنِ أَبِي أُسَيْدٍ إِلَى النَّبِيِّ ﷺ حِينَ وُلِدَ، فَوَضَعَهُ عَلَى فَخِذِهِ، وَأَبُو أُسَيْدٍ جَالِسٌ، فَلَهَى النَّبِيُّ ﷺ بِشَيْءٍ بَيْنَ يَدَيْهِ، وَأَمَرَ أَبُو أُسَيْدٍ بِابْنِهِ فَاحْتُمِلَ مِنْ فَخِذِ النَّبِيِّ ﷺ، فَاسْتَفَاقَ النَّبِيُّ ﷺ فَقَالَ: أَيْنَ الصَّبِيُّ؟ فَقَالَ أَبُو أُسَيْدٍ: قَلَبْنَاهُ يَا رَسُولَ اللهِ، قَالَ: مَا اسْمُهُ؟ قَالَ: فُلاَنٌ، قَالَ: لاَ، لَكِنِ اسْمُهُ الْمُنْذِرُ، فَسَمَّاهُ يَوْمَئِذٍ الْمُنْذِرَ.