So it is obligatory upon us, O gathering of Muslims, to strive towards the rectification of our hearts. And from the greatest reasons for its rectification is supplicating, just as the Prophet ﷺ used to supplicate. Supplicating and resorting to Allāh, the Blessed and Most High, to firmly establish these hearts upon his religion and upon believing in Him, and that He should turn these hearts towards obeying Him, and that He turns it away from disobeying Him.
And likewise, from the reasons that are incumbent upon us to take note of, so as to rectify our hearts with it is; dedication to the Qur’ān, by recitation, memorization, contemplation, understanding, learning and acting (upon it). Allāh, the Exalted, said (what means):
“O mankind! There has come to you a good advice from your Lord (i.e. the Quran, ordering all that is good and forbidding all that is evil), and a healing for that (disease of ignorance, doubt, hypocrisy and differences, etc.) in your breasts, – a guidance and a mercy (explaining lawful and unlawful things, etc.) for the believers.” [Yūnus:57]
(The Qur’ān is) an admonition! (It is) an admonition! However, it is for the living hearts, as Allāh, the Exalted said (what means):
“Verily, therein is indeed a reminder for him who has a heart or gives ear while he is heedful.” [Qāf:37]
This Qur’ān is an admonition for the one who fears and is in awe of Allāh, the Blessed and Most High’s threat.
“But warn by the Quran, him who fears My Threat.” [Qāf:45]
And it is a healing for that which is in the chests.
Ibn al-Qayyim, may Allāh have mercy on him, said: “And all the diseases of the hearts (are one of) diseases of doubts and diseases of desires, and in the Qur’ān is a cure for both forms.”
So devote yourselves to, and be plentiful in the recitation of the Qur’ān. And a day should not pass you by, O servant of Allāh, except that you have read a portion of this Qur’ān.
And likewise, from the reasons that are incumbent upon us to take note of, so as to rectify our hearts with it is; being plentiful in the remembrance of Allāh, the Majestic and Most High. And this is a general (example) after a specific one. Because the Qur’ān is the greatest form of remembrance and the most honourable one. The hearts are put at rest with the remembrance of Allāh, the Majestic and Most High, and it becomes rectified by way of it. And it removes from it vanity. Just as Allāh said (what means):
“Verily, in the remembrance of Allah do hearts find rest.” [ar-Ra’d:28]
And he (the Prophet), may peace and blessings be upon him, said: “The similitude of the one who remembers his Lord and the one who does not remember his Lord, is like the living and dead.”
So, be plentiful in the remembrance of Allāh, the Exalted and Most High, so that these hearts can be rectified.
Shaykh al-Islām Ibn Taymiyyah, may Allāh have mercy on him, said: “Verily Shayṭān is Waswās Khannās (a whisperer that withdraws); when the servant remembers his Lord, he withdraws i.e he distances himself and stays away and when he (the servant) is heedless of the remembrance of his Lord, he (Shayṭān) whispers.”
And due to this he (Shaykh al-Islām) said: “The basis and reason for the descent of false beliefs and corrupt desires into the heart is, heedlessness towards the remembrance of Allāh, the Blessed and Most High.”
Ibn al-Qayyim, may Allāh have mercy on him, said: “When the servant is heedless of Allāh’s remembrance for an hour, Shayṭān overtakes his heart.”
How about when we are heedless for hours?! How about when we are occupied with acts of disobedience and prohibitions?!
So, be devoted to the remembrance of Allāh, the Blessed and Most High. (Remember him with) much remembrance. And the one who remembers Allāh, the Mighty and Majestic, after the prayers, and the one who remembers Allāh in the morning and evening, persistent upon the Adhkār of the morning and evening, verily he is among those who remember Allāh alot.
Then add (to that), at every period and time (the saying of); Tasbeeḥ (Subḥānallāh), it will benefit you, and Tahleel (Laa ilāha illa Allāh), it will benefit you, and Takbeer (Allāh akbar), it will benefit you, and Istighfār (seeking forgiveness) will benefit you, and Taḥmeed (Alḥamdulillāh), it will benefit you. Do not be negligent about any of it. By way of remembrance of Allāh, these hearts will be rectified.