The Messenger of Allah ﷺ said, "The Maghrib prayer is the witr of the daytime prayer, so make your night prayer odd-numbered as well. The night prayer is to be performed in pairs, and the witr is a single rakah at the end of the night."
حدثنا عبد الصمد حدثنا هارون بن إبراهيم الأهوازي حدثنا محمد
أن رسول الله ﷺ قال صلاة المغرب وتر صلاة النهار فأوتروا صلاة الليل وصلاة الليل مثنى مثنى والوتر ركعة من آخر الليل
Its isnad is sahih. Harun bin Ibrahim Ahwazi is Abu Muhammad Basri, whom Ibn Main and Ibn Hibban rated as trustworthy, while Abu Hatim said, "There is no harm in him." The hadith was mentioned earlier at 4847 and its cross-references. It is also found in Ibn Abu Shayba, 2/283, and in Tabarani's Saghir, 1/112. This concludes Hamza's addition. The commentary on it was inadvertently omitted by Shaykh Shakir, may Allah have mercy on him.