It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) commanded to trim the moustache thoroughly and to let the beard grow fully.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 5138
Hadith Gradingحکم دارالسلام:حديث صحيح ، خ : 5893 ، م : 259 .