What is the explanation of the Hadith: "Indeed, they let their moustaches grow long and shave their beards, so differ from them," and what is the meaning of "Al-Jaz" and what is the jurisprudence of the Hadith?

Ibn Umar reported that the Prophet (peace be upon him) mentioned the Majus (Zoroastrians) and said: "They let their mustaches grow long and shave their beards, so act differently from them." And Ibn Umar used to trim his mustache. Al-Jaz (الجز) means to cut. The meaning of the Hadith (definition) is that the Prophet (peace be upon him) criticized the Majus for letting their mustaches grow long and shaving their beards, and commanded to differ from them. In this, there is an emphasis on the Prophet's (peace be upon him) eagerness to avoid imitating the disbelievers, and what indicates this is: "He is not one of us who imitates others," and "Whoever imitates a people is one of them." It also contains a prohibition against shaving beards and letting mustaches grow long, as in the Hadith: "Differ from the polytheists, let your beards grow, and trim your mustaches," and the Hadith narrated by Muslim: "Trim the mustaches and let the beards grow; differ from the Majus." Ibn Hazm asserted that trimming the mustache and letting the beard grow is an obligation. Maymun ibn Mihran conveyed Ibn Umar's practice concerning his mustache. Some scholars preferred trimming the mustache, while others preferred shaving it.