Compiled by Imam Yahya ibn Sharaf al-Nawawi
عن علي رضي الله عنه قال: الوتر ليس بختم كصلاة المكتوبة ولكن سن رسول الله صلى الله عليه وسلم قال: "إن الله وتر يحب الوتر، فأوتروا يا أهل القرآن". ((رواه أبو داود والترمذي)). وقال: حديث حسن.
The Witr prayer is not obligatory as the prescribed Salat (prayers), but the Messenger of Allah (ﷺ) observed it as his regular practice (Sunnah). He (ﷺ) said, "Allah is Witr (single, odd) and loves what is Witr. So perform Witr prayer. O followers of Qur'an, observe Witr (prayer)."[At-Tirmidhi and Abu Dawud].