Tafsir of Al-Mujadilah 58:19

استحوذ عليهم الشيطان فٲنساهم ذكر الله

The Shaytan has overpowered them. So he has made them forget the remembrance of Allah. meaning, Shaytan has taken over their hearts to the point that he made them forget Allah the Exalted and Most Honored. This is what the devil does to those whom he controls. Abu Dawud recorded that Abu Ad-Darda' said that he heard the Messenger of Allah say,

ما من ثﻼثة في قرية وﻻ بدو ﻻ تقام فيهم الصﻼة إﻻ قد استحوذ عليهم الشيطان فعليك بالجماعة فٳنما يٲكل الذيب القاصية

Any three in a village or desert among whom the Salah is not called for, will have the Shaytan control them. Therefore, adhere to the Jama`ah, for the wolf eats from the strayed sheep. Za'idah added that As-Sa'ib said that Jama`ah, refers to, "Praying in congregation.'' Allah the Exalted said,

أوليك حزب الشيطان

They are the party of Shaytan. referring to those who are controlled by the devil and, as a result, forgot the remembrance of Allah,

أﻻ إن حزب الشيطان هم الخاسرون

Verily, it is the party of Shaytan that will be the losers!