What is the prescribed sitting and Taslim procedure for Witr prayers consisting of five, seven, or nine rak'ahs?
Chapter on the Times When Prayer is Prohibited
Al-Mughni
Book of Prayer
Primary text
If the Witr is eleven rak'ahs, a Taslim is made after every two rak'ahs. If it is five rak'ahs, one sits only in the final rak'ah. If it is seven rak'ahs, one sits after the sixth rak'ah, recites the Tashahhud, but does not make Taslim, then stands for the seventh rak'ah, recites Tashahhud, and makes Taslim. If it is nine rak'ahs, one sits only after the eighth rak'ah, recites Tashahhud, then stands for the ninth rak'ah and makes Taslim. The evidence for the five rak'ahs being performed without sitting until the last is the narration from Zayd ibn Thabit and Aisha, who stated that the Prophet would perform five rak'ahs of Witr without sitting except in the last one.
Supporting text
There is a differing opinion from Al-Qadi that for seven rak'ahs, one should not sit until the very last rak'ah, similar to the five rak'ahs. However, the detailed narration from Aisha regarding seven rak'ahs explicitly states sitting after the sixth, making this the definitive ruling over narrations where the number of rak'ahs in that sequence is less explicit regarding intermediate sittings.