I would like to know, what is the wisdom behind growing a beard?

The fundamental principle in Islamic legislation is compliance with the commands of Allah and His Messenger. Among the wisdoms behind the command to grow the beard are:

1. Distinguishing oneself from the polytheists (mushrikin); based on the Prophet, peace be upon him, saying: "Be different from the polytheists: trim closely the moustaches and let the beards grow." 2. Differentiating between men and women. 3. Emulating the guidance of the Messengers, as indicated by Harun's (Aaron's) statement, peace be upon him: "(He) said, 'O son of my mother, do not seize me by my beard or by my head.'" Ibn al-Qayyim also mentioned that it encompasses adornment, dignity, and awe.