Mukhtasar Muslim (Abridged) 184 — Trim the mustache and let the beard

It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: (In all words and actions) oppose the polytheists; trim the moustaches and let the beards grow (that is, leave the beards and do not trim them).