Musannaf Ibn Abi Shaybah 39127 — The obligation of witr: Abu Hanifah

Ja'far narrates from his father that the Prophet (peace and blessings be upon him) used to give the sermon standing. Then he (peace and blessings be upon him) would sit, then he (peace and blessings be upon him) would stand, and so he (peace and blessings be upon him) would deliver two sermons.