This is referred to by Imām as-Sādiq (' a ) as is stated in...

This is referred to by Imām as-Sādiq (' a ) as is stated in Misbāh ash - Sharī'ah (the Torch of the Islamic Law). He said: “Let your heart be your tongue's qiblah , and do not move it except by the heart's order, the reason's assent and the faith's consent.” [^1] At the beginning, before the tongue learns talking, the sālik on the way to the Hereafter is to teach it and to instruct it, in tranquility and quietude, with the supplications.

As soon as the heart finds its tongue, it becomes the qiblah (the focus of attraction) of the mouth's tongue and of the other organs of the body. When it starts supplication, the whole kingdom of the human existence becomes supplicant.

But if the noble supplication is recited without the tranquility and calmness of the heart, but with haste, trouble, and unbalanced senses, it will have no effect on the heart, and will not pass the limits of the animal tongue and ear of the outer body to the interior and the human hearing, and its truth will not be implemented in the core of the heart, nor will it become a perfect and non-transitory image of the heart.

Thus, when there are terrors and difficulties, especially the terrors of the agonies of death and the difficulties of the throes of the last breaths, one completely forgets supplication and it will be erased from the plane of the heart.

Even the name of Allah the Exalted, the Seal of the Prophets ( s ), the noble religion of Islam, the divine sacred Book, the Imāms of guidance (' a ) and other knowledge [ ma'ārif ] which have not been conveyed to the heart, will be forgotten, and when he is questioned in the grave, he cannot answer, and the talqīn will be of no avail, because he does not find in himself any trace of the truth of Lordship, prophethood or other knowledge [ ma'ārif ], and that what he used to chatter about, and had no image of in his heart, vanishes from his memory, and thus he will have no share of testifying the Lordship, prophethood and other knowledge [ ma'ārif ].

It is stated in a hadīth that a group of the people [ ummah ] of the Messenger of Allah ( s ), on being entered into Hell, forget the name of the Prophet because of the fearfulness of the Hell-keeper, despite the fact that the same hadīth states that they are of the believers and their hearts and features glitter brightly because of the light of faith.