Is it permissible to abandon and harm a neighbor in retaliation for their harm and mockery, based on the Almighty's saying: "And the recompense of an evil is an evil like thereof"?

Returning a greeting to a Muslim is obligatory. However, it is permissible not to return a greeting to a fasiq (open sinner) or an abusive person as a deterrent, especially if their harm is severe and continuous. Consideration of benefit is essential; if not returning the greeting increases the harm, then the default is to return it. It is preferable to endure the harm of a neighbor and treat them kindly, following the example of the Quran and Sunnah (definition), for that is better and yields greater reward.