The Messenger of Allah ﷺ said, "If it would not be too difficult for my community, I would have ordered them to use the siwak before every prayer."So Zayd bin Khalid used to keep his siwak in the place where a scribe keeps his pen behind the ear, and whenever he stood up to pray, he would brush his teeth with it.
حدثنا عبد الصمد قال حدثنا حرب يعني ابن شداد عن يحيى حدثنا أبو سلمة وحدثنا أبي حدثنا محمد بن فضيل عن محمد بن إسحاق عن محمد بن إبراهيم عن أبي سلمة
قال رسول الله ﷺ لولا أن أشق على أمتي لأمرتهم بالسواك عند كل صلاة قال فكان زيد بن خالد يضع السواك منه موضع القلم من أذن الكاتب كلما قام إلى الصلاة استاك
Its isnad is sahih, it has already appeared through its first route, and it is hasan through the second, and it has already appeared at 16969.