What is the authenticity of the report from Ibn 'Umar that he used to trim his beard?

We hope for clarification on the extent of the authenticity of the saying attributed to Ibn 'Umar, which states: that he used to take from his beard whatever exceeded a handful?

Answer:
This is well-known from Ibn 'Umar, and it is known that he (may Allah be pleased with him) , when he was in Hajj or in 'Umrah, would interpret the saying of Allah the Exalted: [Surat al-Hajj:29]. So he would take what exceeded a handful in his Hajj and 'Umrah. When he shortened his hair, he would take what exceeded a handful, meaning he would grasp his beard with his hand, and whatever hung below... he would take it after that. This is what is narrated from him, and it is established from him, but it was his opinion and his independent legal reasoning.
And the correct view is: that he does not take anything. The saying of the Prophet (peace and blessings be upon him) takes precedence over Ibn 'Umar, and over anyone else. The Prophet (peace and blessings be upon him) said: He did not say: except what exceeds a handful. He said: And he said: And he did not say: except what exceeds a handful (peace and blessings be upon him). But this was hidden from Ibn 'Umar, and he exercised independent legal reasoning, and he thought that it was included in His saying: [Surat al-Hajj:29]. This is the weaker position, even if Ibn 'Umar did it. Because the general rule is: that the saying of a Companion, or the saying of a scholar, if it contradicts the Sunnah, the Sunnah takes precedence over it, and one does not turn to the saying of the Companion, or to anyone else. Because Allah says: [Surat al-Nisa:59].
And He says, Exalted is He: [Surat al-Shura:10]. So when there is disagreement among the Companions or among the scholars regarding something, it is obligatory to refer it to Allah, and to the Qur'an, and to the Messenger during his lifetime, and to the Sunnah after his death (peace and blessings be upon him). So what is found in the Qur'an and the Sunnah regarding the matter is the judge, it is the one that takes precedence.

Question: Is it permissible to trim the beard, O Shaykh?

Answer: It is not permissible to trim it, nor to shave it. Rather, that is forbidden, and it is not permissible for a Muslim to trim his beard, nor to shave it. Because this is what is wrong, and it contradicts what Allah and His Messenger commanded.