It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: If I had not feared hardship for my ummah, I would have commanded them to use the miswak at every time of ablution.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 10696