Praise be to Allah.
Shaving the beard is haram because of the sahih ahadith that clearly state this, and because of the general application of texts that forbid resembling the unbelievers.
Ibn ‘Umar narrated that the Messenger of Allah (peace and blessings of Allah be upon him) said: “Be different from the polytheists; let your beards grow and trim your moustaches.” According to another report: “Trim your moustaches and let your beards grow .”
There are other hadith which convey the same meaning, which is to leave the beard as it is and let it grow long, without shaving, plucking or cutting any part of it.
Ibn Hazm reported that there was scholarly consensus that it is an obligation to trim the moustache and let the beard grow . He quoted a number of ahadith as evidence, including the hadith of Ibn ‘Umar (may Allah be pleased with him) quoted above, and the hadith of Zayd ibn Arqam in which the Prophet (peace and blessings of Allah be upon him) said: “Whoever does not remove any of his moustache is not one of us.” (Classed as sahih by al-Tirmidhi).
Ibn Hazm said in al-Furu’: “This formula according to our colleagues [i.e., the Hanbalis] means that it is haram to shave the beard .”
Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him) said:
“The Quran, Sunnah and ijma’ (scholarly consensus) all indicate that we must differ from the unbelievers in all aspects and not imitate them, because imitating them on the outside will make us imitate them in their bad deeds and habits, and even in beliefs, which will result in befriending them in our hearts, just as loving them in our hearts will lead to imitating them on the outside. Al-Tirmidhi reported that the Messenger of Allah (peace and blessings of Allah be upon him) said, “He is not one of us who imitates people other than us. Do not imitate the Jews and Christians.” According to another version: “Whoever imitates a people is one of them. ” (Reported by al-Imam Ahmad)
‘Umar ibn al-Khattab rejected the testimony of the person who plucked his beard. Al-Imam Ibn ‘Abd al-Barr said in al-Tamhid: “It is forbidden to shave the beard, and no one does this except men who are effeminate” i.e., those who imitate women. The Prophet (peace and blessings of Allah be upon him) had a thick beard (reported by Muslim from Jabir). It is not permitted to remove any part of the beard because of the general meaning of the texts which forbid doing so.”
And Allah knows best.