Abu Tamim, Some scholars would argue that the Hadith implies one should keep a beard (whether wajib or mandub, let us leave that), and that: 1) Actions of Sahaba are not hujjah, and this is technically, more or less, a principle in ShafiŽi Usul. 2) If it is to be taken as a hujjah (or at the very least at least a source of guidance), a Sahabi trimming his beard would only indicate that it is not impermissible to do so, and the specific length he trimmed it down to would not necessitate it being a defined limit as such, as there is no text expressing such. This is why you will find an Imam of the ShafiŽi school like Al-Ghazali (rah) saying that keeping a short beard fulfills the Sunah of the beard. We may agree or disagree. wa'Allahu aŽlam.