The Messenger of Allah ﷺ ordered that mustaches be trimmed short and beards be left to grow.
حدثنا عبد الله بن مسلمة القعنبي عن مالك عن أبي بكر بن نافع عن أبيه
أن رسول الله ﷺ أمر بإحفاء الشوارب وإعفاء اللحى
Muslim narrated it in the Book of Purification, chapter on the characteristics of fitrah, hadith no. 2:59, from the hadith of Malik through the same chain. It is found in Muwatta (Yahya), 2/947. Bukhari also narrated it, hadith nos. 5892 and 5893, from the hadith of Nafi through the same chain, with a similar meaning.