Hadith: I do not think that so-and-so and so-and-so know anything about our religion

عن عائشة رضي الله عنها قالت: قال رسول الله صلى الله عليه وسلم : «ما أُظُن فُلَانا وفُلَانا يَعْرِفَان من دِيِننَا شَيْئَا». قال اللَّيث بن سعد أحد رُواة هذا الحديث: هذان الرجلان كانا من المنافقين.
[صحيح] - [رواه البخاري]

‘Ā'ishah (may Allah be pleased with her) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) said: "I do not think that so-and-so and so-and-so know anything about our religion." Al-Layth ibn Sa‘d (one of the narrators of the Hadīth) said: "These two men were from the hypocrites."
[Authentic hadith] - [Narrated by Bukhari]

Explanation

‘Ā'ishah (may Allah be pleased with her) reported that the Prophet (may Allah's peace and blessings be upon him) informed her about two men and mentioned that they knew nothing about Islam, because they were showing Islam and hiding their disbelief. The fact that the Prophet (may Allah's peace and blessings be upon him) mentioned these two men in their absence is not considered backbiting, which is forbidden; rather, it is necessary to disclose their reality, so that people who do not know them would not be deceived by their apparent status. The Prophet's statement in this context implies certainty, because the Prophet (may Allah's peace and blessings be upon him) was in fact aware of the hypocrites through revelation from Allah in Sūrat At-Tawbah. Ibn ‘Abbās (may Allah be pleased with him) said: We used to call Sūrat At-Tawbah "Al-Fādihah" (the exposing chapter). Ibn ‘Abbās (may Allah be pleased with him) said: "The verses continued to be revealed and exposing the hypocrites until we were worried (lest we should be counted among them)."