And when sins blind the heart, how about the greatest of them? He explained it by saying: ﴿That﴾ meaning the great matter of being far from good, which is lying by informing with false testimony and swearing to the truth while turning away from the path and describing their actions with evil ﴿Because they believed﴾ meaning because they acknowledged faith with their tongues without matching it with their hearts. And when disbelief is unlikely, how about when it comes after acknowledgment? He expressed it with a tool of distance for that reason, so that you may understand the blame on the subsequent matter as a priority, and so that it is not assumed that the blame is only on the subsequent disbelief after faith, not on it in general. Thus, the expression with 'then' indicates that whoever persists throughout his life on faith and then disbelieves just before his death for a moment, he has this blame. He said: ﴿Then they disbelieved﴾ meaning secretly, so they feared the people and did not fear Allah. And when mere sealing on the heart is extremely ugly, it is understood as an ugliness of what came from Allah by priority. The saying: ﴿So it was sealed﴾ means that sealing occurred, which is the stamp, while it is known that only He, glorified and exalted is He, is capable of that ﴿upon their hearts﴾ due to their transgression of the greatest of the major sins in hypocrisy, until they became accustomed to disbelief and firmly established in it. Likewise, whoever abandons the Friday prayer three times out of negligence, it resulted in that they ﴿do not understand﴾ meaning they do not have understanding in anything of the matters, so they do not distinguish right from wrong nor truth from falsehood, for the one who is sealed upon does not receive anything nor does anything come out from him.