All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
It is confirmed that the Prophet 'had a thick beard'. [An-Nasaa'ee] This means that the Prophet's beard was not thin or long but it was thick or dense but not too long i.e. it did not reach his chest. Imaam Ahmad reported that the Prophet's beard was down to his lower part of his throat. This narration is considered weak by Shaykh Al-Arna'oot. This implies that the Prophet's beard was not too long. Even if his beard was too long, it does not mean that when some companions cut a part from their beards which was beyond a fist's length that they acted contrarily to the Prophet's guidance regarding keeping a long beard, unless it is proven that his beard was very long and he never took anything from it.
Indeed it is reported that some companions, like 'Ali, Abu Hurayrah, and 'Abdullaah Ibn 'Umar and a group of righteous predecessors used to trim from their beard whatever exceeded a fist's length, whether this was during Hajj or 'Umrah.
Allaah Knows best.