Ihanath,Qianat, betrayal. This is one of the biggest challenges facing the Islamic world at any time. The harassment of the hypocrites was severe during the time of the Prophet.
Pretend to be a Muslim and live like a true believer to the satisfaction of the Prophet and his followers. These believers were then subjected to various persecutions, such as stabbing them in the back, retreating from the battlefield, and handing over their plans and decisions to the enemy.
Hudayfat ibn Yaman (ra) was one of the closest of prophet Muhammad's Companions. When he saw someone, he could tell without being mistaken whether he was a believer or a hypocrite. He was able to do this through a technique taught only by the Prophet. Hudayfah, his father and brother converted to Islam in Uhd. But his father, Yaman, was killed by Muslims at that war without knowing that he had converted to Islam. Omar (ra) once asked him to tell him the names of the hypocrites, but he refused. Then Umar(ra) asked :"Hudayfah, have you seen any of the signs of those hypocrites in this Umar ...? Hudayfa replied :" If I had seen anything like that, I would have informed you. Then Umar (ra) would not have attended the funeral prayers which he did not attend. Ibn Hajar al-Haytami (ra) says: Hudayfah (ra) knew about all the fitnas that would happen on earth until the Day of Resurrection.