Is it permissible to lower one's gaze to avoid seeing evils that one might be obligated to denounce, knowing that this action might not be good?

Enjoining good and forbidding evil is obligatory upon whoever knows and witnesses an evil with certainty. As for averting one's gaze from evils, there is no sin in it, as it is not obligatory to seek out evils in the streets. This is because that without which an obligation cannot be fulfilled is not itself an obligation. Rather, seeking out evil is considered an idle gaze ( فضول النظر ) which is disliked, and it may lead to falling into unlawful gazing. The obligatory gaze is that which aids in learning obligations or distinguishing lawful from unlawful. The recommended gaze is that which increases faith and knowledge. As for the disliked gaze, it is an idle gaze in which there is no benefit.