Tafsir of At-Tawbah 9:77

فٲعقبهم نفاقا في قلوبهم إلى يوم يلقونه

And of them are some who made a covenant with Allah (saying): "If He bestowed on us of His bounty, we will verily, give Sadaqah and will be certainly among the righteous.'' Then when He gave them of His bounty, they became stingy, and turned away, averse. So He punished them by putting hypocrisy into their hearts till the Day whereon they shall meet Him, Allah says, some hypocrites give Allah their strongest oaths that if He enriches them from His bounty, they will give away alms and be among the righteous. However, they did not fulfill their vows or say the truth with their words. The consequence of this action is that hypocrisy was placed in their hearts until the Day they meet Allah the Exalted, on the Day of Resurrection. We seek refuge with Allah from such an end. Allah said,

بما أخلفوا الله ما وعدوه

...because they broke that (covenant) with Allah which they had promised to Him) He placed hypocrisy in their hearts because they broke their promise and lied.

وبما كانوا يكذبون

and because they used to tell lies. In the Two Sahihs, it is recorded that the Messenger of Allah said,

آية المنافق ثﻼث

إذا حدث كذب

وإذا وعد أخلف

وإذا ايتمن خان

There are three signs for a hypocrite: if he speaks, he lies; if he promises, he breaks the promise; and if he is entrusted, he betrays the trust. Allah said,