Hadeeth of Tammam bin al 'Abbas bin 'Abdul Muttalib from the Prophet

They came to the Prophet (ﷺ) , or someone came to him, and he said: “Why do I see you coming to me with yellow and dirty teeth? Use the siwak. Were it not that it would be too difficult for my ummah, I would have obliged them to use the siwak as I have obliged them to do wudoo’."

The Messenger of Allah (ﷺ) used to line up "Abdullah, ‘Ubaidullah and Katheer, the sons of al-"Abbas, then he would say: “Whoever reaches me first will have such and such." Then they would race towards him and fall on his back and chest, and he would kiss them and hug them.