It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Were it not that I would burden my Ummah, I would have ordered them to use the miswak at every prayer."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13535