Wa alaykum salam wa rahmatuLlah,

Imam Nawawi states in both Minhaj al-Talibin and Rawdah al-Talibin, that the witr prayer is sunnah. Also, the witr prayer can be performed by one rakah alone, three, five, seven, nine, or eleven, which is the maximum upon the preferred opinion of the madhhab. The second opinion in the madhhab states that its maximum number is thirteen rakah and that it is not permitted to exceed this number. If he does increase beyond the maximum number of rakah, then his witr will be invalid. It is sunnah for one who only makes three rakah that he recites in the first Surah al-Ala, in the second Surah al-Kafirun, and in the third Surah al-Ikhlas, Surah al-Falaq, and Surah al-Nas. (Mughni al-Muhtaj 1/451-52: Rawdah al-Talibin 1/328)

Allah knows best.

Answered by: Sidi Mahmud Adams