What is the meaning of Ibn Abbas's saying (may Allah be pleased with them both): "From where do you think the donkey got it?"

If the statement about Ibn Abbas is authentic, then it is his disapproval of Muawiyah's performing the witr prayer with a single rak'ah, because he disliked a man performing witr with one rak'ah without preceding it with voluntary prayers. Al-Tahawi, in "Sharh Ma'ani al-Athar," reported something indicating that Ibn Abbas said, "Muawiyah was correct," when asked about Muawiyah's performing witr with a single rak'ah, and that might have been out of dissimulation (taqiyya). It has been authentically reported from the Prophet, peace and blessings be upon him, that he said: "Witr is a duty, so whoever wishes may perform witr with seven [rak'ahs], and whoever wishes may perform witr with five, and whoever wishes may perform witr with three, and whoever wishes may perform witr with one."