Musannaf Ibn Abi Shaybah 1802 — What is mentioned about the siwak

It is narrated from Sayyiduna Zayd bin Khalid (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Were it not that I feared hardship for my Ummah, I would have commanded them to use the miswak for every prayer." Sayyiduna Zayd bin Khalid used to keep his miswak on his ear, at the place where a scribe keeps his pen. Whenever he stood up for prayer, he would use the miswak and then put it back in its place.