Hudhayfah bin al-Yaman said that the Messenger of Allah (sallAllahu ‘alaihi wa sallam) said, "Trials and tribulation will be presented to the heart [one after another] in the same way that the mat is knitted together, reed by reed. Any heart that accepts them will have a black spot form on it. Any heart that rejects them will have a white spot put on it until the hearts end up being one of two types: a black heart, murky and like an overturned vessel, it does not know the good and does not reject the evil, all it knows is its base desires; and a white heart which will not be harmed by trials for as long as the heavens and the earth remain."
Hence he likened the onset of trials upon the heart to knotting the reeds of a mat, one after the other.
He divided the hearts into two types based on how they react to these trials:
1. A heart that infuses trials when exposed to them in the same way that a sponge soaks in water. Therefore it has a black spot form on it, and it will keep on accepting these trials until it becomes totally black and inverted. This is the meaning of his saying, 'like an overturned vessel' i.e. inverted. Then when it becomes black and inverted, it is subjugated to the following two dangerous diseases that push it to destruction:
a. Its confusion of good and evil such that it does not know the good or reject the evil. It is also possible that its disease dupe a person into believing good to be evil, evil to be good, Sunnah to be bid'ah, bid'ah to be Sunnah, truth to be falsehood, and falsehood to be truth.
b. Its giving precedence to its base desires when seeking judgement rather than that which the Messenger (sallAllahu ‘alaihi wa sallam) came with, its yielding to them, and following them.
2. A white heart that has been set ablaze with the light of faith and its niche has been illuminated. When a trial is presented to it, it rejects it and repels it and hence its light, blaze, and strength increase.
The trials that are presented to the hearts are the causes of its disease. They are the trials of carnal desires and doubts, the trials of aimless wandering and misguidance, the trials of sins and innovations, and the trials of oppression and ignorance. The first type lead to the corruption of desire and intent and the second type lead to the corruption of knowledge and belief.
The Companions (may Allah be pleased with them) divided the hearts into four categories as is authentically reported from Hudhayfah bin al-Yaman, 'The hearts are of four types: The heart that has exclusively been illuminated by a blazing torch and that is the heart of the believer; the heart that is encased and that is the heart of the disbeliever; the heart that is inverted and that is the heart of the hypocrite - he knew only to reject, and he saw only to become blind; and the heart that has two impulses: an impulse calling it to faith and an impulse calling it to hypocrisy: it belongs to the impulse that is most prominent.'
The meaning of his saying, 'a heart that has exclusively...' means a heart that has detached itself of everything besides Allah and His Messenger. Therefore it has separated and secured itself from everything save the truth.
The meaning of his saying, 'illuminated by a blazing torch' refers to the niche of faith. Therefore he indicated by his words, ‘that has exclusively...’ that is secure from false doubts and misguiding carnal desires. He indicated by his words, 'a blazing torch' that it was set ablaze and illuminated by the light of knowledge and faith.
The 'encased heart' refers to the heart of the disbeliever because it is wrapped by a veil and covering and hence the light of knowledge and faith cannot reach it. This is as Allah said, relating from the Jews that,
“They say: our hearts are wrapped...” [Surah Al-Baqarah (2): 88]
This veil is the covering that Allah has placed on their hearts by way of punishment for their rejecting the truth and being too arrogant to accept it. Therefore it is a covering upon the hearts, a seal for the ears, and blindness for the eyes. This is the obscuring screen upon the eyes talked about in His saying,
“And when you recite the Qur'an, We out between you and those who believe not in the Hereafter, an obscuring screen. We have put coverings over their hearts lest they should understand it and deafness in their ears.” [Surah Al-Isra' (17): 45-4-6J
When the people who have these types of hearts are admonished to purify their Tawhid and following ittiba), they turn on their heels and run!
The 'inverted heart' refers to the heart of the hypocrite as Allah, the Exalted says,
“Then what is the matter with you that you are divided into two parties regarding the hypocrites? Allah has cast them back [to disbelief] because of what they have earned.” [Surah An-Nisa’ (4): 88]
Meaning: he caused them to relapse and return to the falsehood that they used to be in due to their working false deeds.
This is the most evil of hearts and the vilest of them for it believes falsehood to be the truth and shows love and allegiance to those who follow it. It also believes the truth to be falsehood and displays enmity to those who follow it. The Aid of Allah is sought!
The 'heart that has two urges’ refers to the heart that is not entrenched in faith because it has not devoted itself solely to the truth that Allah sent His Messenger with. Instead it contains some faith and some of its opposite: it is closer to disbelief than faith sometimes; and at other times it is closer to faith than disbelief. The heart follows whatever is most influential at that time.
 Carnal desires.
 Reported by ibn Abi Shaybah, al-lman [p. 17] and others with a sahih isnad.
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