Sayyiduna al-Mughirah bin Shu'bah (may Allah be pleased with him) narrated that the Messenger of Allah (peace and blessings be upon him) saw a man with a long moustache, so he called for a tooth-stick (miswak) and a blade; then he (peace and blessings be upon him) placed the tooth-stick under the moustache and trimmed it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 695
Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said: The Messenger of Allah (peace and blessings be upon him) mentioned the Magians and said: "They let their moustaches grow and shave their beards, so oppose them." The narrator said: Sayyiduna Ibn Umar (may Allah be pleased with them both) would take hold of his moustache across its width and clip it, just as a sheep or a camel is shorn.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 696
Hadith Gradingمحدثین:حسن
Hadith Takhrij«حسن۔ أخرجه الطبراني في الاوسط 51/1»
Ubaydullah bin Abi Rafi' (may Allah have mercy on him) narrated: I saw Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him), Jabir bin Abdullah (may Allah be pleased with them both), Ibn Umar (may Allah be pleased with them both), Rafi' bin Khadij (may Allah be pleased with him), Abu Usayd al-Ansari (may Allah be pleased with him), Ibn al-Akwa' (may Allah be pleased with him) and Abu Rafi' (may Allah be pleased with him) trimming their moustaches so closely that it was almost shaving.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 697
Shurahbil bin Muslim al-Khawlani (may Allah have mercy on him) said: I saw five of the Companions (may Allah be pleased with them) who used to trim their moustaches, let their beards grow and dye them: Abu Umamah al-Bahili, Abdullah bin Busr, Utbah bin Abd al-Sulami, al-Hajjaj bin Amir al-Thumali and al-Miqdam bin Ma'dikarib al-Kindi (may Allah be pleased with them). All of them used to trim their moustaches from the side of the lip.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 698
Hadith Gradingمحدثین:حسن
Hadith Takhrij«حسن۔ أخرجه الطبراني في الكبير 3218»
Malik bin Anas (may Allah have mercy on him) mentioned some people's removing their moustaches down to the root. Imam Malik (may Allah have mercy on him) said: Whoever does such a thing deserves to be reprimanded, for there is no hadith from the Prophet (peace and blessings be upon him) about removing the moustache down to the root; rather, one should trim from the side of both lips and the mouth. Malik bin Anas (may Allah have mercy on him) said: Shaving the moustache from the root is an innovation that has appeared among the people.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 699
(a) Abdullah bin Maslamah al-Qa'nabi narrates it from Malik (may Allah have mercy on him).
(b) It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that he (peace and blessings be upon him) ordered "trimming the moustaches and letting the beard grow," and the wording of al-Qa'nabi's hadith is that the Messenger of Allah (peace and blessings be upon him) ordered "trimming the moustache and letting the beard grow."
(b) It is as though the Imam took ihfa' to mean trimming the moustache thoroughly, not shaving it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 700