The Prophet ﷺ said, "Why do I see you coming to me with unkempt hair? Would it not be difficult for my Ummah (nation) if I were to impose the use of Siwak (tooth-cleaning twig) on them, just as I have made Wudu (ablution) obligatory upon them?"  

أَتَوْا النَّبِيَّ ﷺ أَوِ أتِيَ فَقَالَ مَا لِي أَرَاكُمْ تَأْتُونِي قُلْحًا اسْتَاكُوا لَوْلا أَنْ أَشُقَّ عَلَى أُمَّتِي لَفَرَضْتُ عَلَيْهِمُ السِّوَاكَ كَمَا فَرَضْتُ عَلَيْهِمِ الْوُضُوءَ  

[Machine] The Messenger of Allah ﷺ used to describe Abdullah, Ubaidullah, and many among the Banu Abbas, then he would say, "Whoever comes to me first, he shall have this and this." So they would race towards him and fall on his back and chest, and he would kiss them and hold them tightly.  

كَانَ رَسُولُ اللهِ ﷺ يَصُفُّ عَبْدَ اللهِ وَعُبَيْدَ اللهِ وَكُثَيَّرًا بَنِي الْعَبَّاسِ ثُمَّ يَقُولُ مَنْ سَبَقَ إِلَيَّ فَلَهُ كَذَا وَكَذَا قَالَ فَيَسْتَبِقُونَ إِلَيْهِ فَيَقَعُونَ عَلَى ظَهْرِهِ وَصَدْرِهِ فَيُقَبِّلُهُمْ وَيَلْتَزَمُهُمْ