What is the ruling on growing a beard and trimming the mustache, along with citing and referencing the evidence, and is one who shaves his beard considered sinful and subject to punishment in this world or the Hereafter?

The Prophet, peace and blessings be upon him, commanded the letting of the beard grow and the trimming of the mustache. This is supported by authentic and explicit hadiths, including his saying, peace and blessings be upon him: "Trim the mustaches and let the beards grow; be different from the polytheists," and his saying: "Trim the mustaches and let the beards hang; be different from the Majus (Zoroastrians)." The command to let the beard grow implies a prohibition against shaving it or shortening it. As for trimming the mustache, the preferred view is that it should be trimmed until the edge of the lip becomes visible, without removing it completely from its root.