Did the Companions know the hypocrites during the time of the Prophet (peace and blessings be upon him)?

Question:
The benefits of the explanation of the book *Iqtida' al-Sirat al-Mustaqim li-Mukhalafat Ahl al-Jahim* by Ibn Taymiyyah. Shaykh, even in this time and in the time of the Prophet (peace and blessings be upon him), no one knew the names of the hypocrites except as Allah informed His Messenger, and then he kept it secret from Hudhayfah (may Allah be pleased with him); no one knew that so-and-so was a hypocrite by his specific identity. That is, it is possible that a Muslim or a listener now, hearing your words, might think well of someone or think ill of them, and , but how is it that anyone can say this person is a hypocrite or this person is not a hypocrite, or judge him by his words or his actions? Or by his absence from the prayer, as Ibn Mas'ud said: "No one is absent from it except a hypocrite whose hypocrisy is known."

Answer:
The issue of doctrinal hypocrisy is known only to Allah (Glorified and Exalted is He), because it is an act of the heart. As for practical hypocrisy, it appears by one engaging in some of the characteristics of the hypocrites, such as his delay in attending the congregational prayer; this is a sign of hypocrisy. His hatred of charity is a sign of hypocrisy, and it appears on him and is known from him. And lying: if he speaks, he lies; if he promises, he breaks his promise; and if he is trusted, he betrays. This is the sign of the hypocrite, meaning his mark by which he is known. Allah (Mighty and Majestic) says: , so what they conceal of hypocrisy appears in the slips of their tongues and the expressions of their faces. But we have only the outward appearance.