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.
The Muslim is enjoined to grow his beard, as evidenced by the hadeeth narrated on the authority of Abu Hurayrah who related that the Prophet said, "Trim the mustache closely and let the beard grow, and thus act differently from the fire-worshippers." [Muslim] It was also narrated on the authority of Ibn ʻUmar that the Prophet said, "Let the beard grow and trim the mustache." [Al-Bukhari]
When the Muslim man lets his beard grow for worldly purposes such as being stylish, for instance, and not for the purpose of worship and obeying the command of the Prophet in this regard, then he is denied the reward for obeying the command of the Prophet and following his example. The Prophet said, "Verily, the reward of a deed depends on the intention; and verily every person will be rewarded according to his intention; so whoever emigrated for worldly benefits or to marry a woman, then his emigration is for that for which he emigrated..." [Al-Bukhari and Muslim]
It cannot be said, though, that it is prohibited for the Muslim man to grow his beard in this case or that he is obliged to shave his beard. This situation is similar to a person performing obligatory prayers merely to show off and out of ostentation; in this case, he fails to earn the rewards for performing the prayers and bears a sin for showing off and ostentation; however, it cannot be said that he must refrain from performing obligatory prayers or that it is prohibited for him to perform them. Rather, he should be told to perform the obligatory prayers and strive to change his invalid intention.
The same applies to the Muslim who grows his beard with an invalid intention; holding such an intention is deemed either disliked or prohibited. However, letting the beard grow is obligatory on the Muslim man and conforms to the sharee'ah. When the adult Muslim grows his beard with an invalid intention, he fails to earn the rewards for this religious obligation and perhaps bear a sin for that.
Please, refer to fataawa 81978 and 84474about the obligation of letting the beard grow and the prohibition of shaving it.
Allaah knows best.