what is the devil's trap?

Devil's trap

The devil has no surer and more effective way than creating separation between people.

Whenever he wants to deceive two people, he separates them first.

Whenever you are going to have bread. firstly, you would divide it into small bites to be able to eat. If you can't cut it, you will give up eating.

if he could not separate a crowd, gets frustrated and leaves.

In this regard Quran says:

Tell My servants to speak in a manner which is the best. Indeed Satan incites ill feelings between them, and Satan is indeed man’s manifest enemy.[1]

[1]-  Quran. Surah 17. 53