What is the legitimate Shar'i constraint that removes the obligation of enjoining good and forbidding evil when condemning someone who shaves his beard, especially in situations where it is difficult to determine the hardship, and is psychological distress considered a barrier to such condemnation?

Shaving the beard is contrary to the Sunnah and is prohibited according to the majority of scholars. Denouncing this act is a good deed for which a Muslim is rewarded, but its obligation is conditional upon ability and the absence of significant hardship or difficulty.

Therefore, it is not obligatory to denounce a beard-shaver every time one is seen, due to the difficulty and hardship involved. Indeed, jurists have stipulated that the obligation of denunciation is waived if the reprehensible act becomes widespread to the extent that it is difficult to denounce it.

Thus, a Muslim is not obligated to denounce every reprehensible act he witnesses in the marketplace due to their abundance. Rather, he should denounce them whenever it is feasible for him to do so, and the obligation is removed in the presence of hardship or difficulty.