Bukhari

Hadith Commentary:
(1)
The meaning of "Muqallib al-Qulub" is that Allah, the Exalted, turns the heart of a servant from faith (iman) towards adopting disbelief (kufr), and from disbelief towards adopting faith, that is, He is capable of making a believer into a disbeliever and causing a disbeliever to adopt disbelief. In one hadith, it is mentioned that the example of a human heart is like a feather lying in an open plain, and strong, fierce winds keep turning it over, sometimes upright and sometimes upside down. (Musnad Ahmad: 4/419) What comparison can there be between a strong, fierce wind in a vast forest and a tiny feather?
(2)
Imam Bukhari rahimahullah has explained the meaning of Allah, the Exalted, coming between a servant and his heart in the noble verse as referring to the turning of the heart’s intentions. This is clarified by another hadith, in which the Messenger of Allah sallallahu alayhi wa sallam said: “All the hearts of mankind are between two fingers from among the fingers of the Most Merciful (ar-Rahman); He turns them as He wills.” After this, the Messenger of Allah sallallahu alayhi wa sallam supplicated in these words: “O Turner of the hearts! Keep our hearts inclined towards Your obedience.” (Musnad Ahmad: 6/251)
(3)
The absolute power of the Truth (Allah), the Exalted, and the utter helplessness of the servants cannot be depicted in a manner more effective and concise than this. When the noble Companions radi Allahu anhum heard this supplication from the Messenger of Allah sallallahu alayhi wa sallam, they began to ask: “Now that we have believed in you, is there still any danger concerning us?” So he repeated the same words that have already been mentioned in the first hadith. (Jami‘ at-Tirmidhi, al-Qadr, Hadith: 2140) This means that even after attaining the rank of Companionship, no person can be free from fear of the overwhelming decree and predestination (qada wa qadar). The essence of servitude is that even after reaching the highest of ranks, a person continues to fear the absolute authority of the All-Powerful. From this, it should also be kept in mind that the noble Companions radi Allahu anhum, who were to a great extent protected from such dangers, when they received this answer from the Prophetic court, then what can be said about people as weak and feeble as us? And Allah is the One whose help is sought.

Hadith Commentary:
From this hadith, it is derived that swearing an oath by an attribute of Allah is valid, and it will be considered a legal (shar‘i) oath. If necessary, its expiation (kaffarah) will also become obligatory.

Hadith Commentary:
I will not say this, nor will I do this—by the One who turns the hearts. The turning of the hearts is also an attribute of Allah, and it is in His hand alone. He is absolutely unique and without partner in this attribute as well.

Hadith Commentary:
➊
In one narration, it is mentioned that the Messenger of Allah (sallallahu alayhi wa sallam) would frequently swear in this manner:
(لا، وَمُصَرّف القلوب)
"By the One Who turns the hearts."
(Sunan Ibn Majah, Al-Kaffarat, Hadith: 2092)
Hafiz Ibn Hajar rahimahullah, while explaining this hadith, writes that all the actions of the heart are created by Allah, such as:
the heart's intention, the arising of any desire within it, as well as its turning from one state to another, etc.
(Fath al-Bari: 11/642)

➋
The heart is called "qalb" because it frequently turns from one state to another, even though the turning of the heart is from Allah, as is evident from the statement of the Messenger of Allah (sallallahu alayhi wa sallam):
"All the hearts of the children of Adam are between two fingers of the Merciful, as if they are one heart. He turns them as He wills." Then the Messenger of Allah (sallallahu alayhi wa sallam) would say: "O Turner of the hearts! Turn our hearts towards Your obedience."
(Sahih Muslim, Al-Qadr, Hadith: 6750) (2654)

➌
The turning of the hearts is an active attribute (sifah fi‘liyya) whose reference is to Allah's power (qudrah). The active attributes, in terms of their nature, are eternal (qadim), but in relation to the servant, they are contingent (hadith). Allah, from pre-eternity, is the Creator in terms of His essence and attributes; everything besides Him is created.
None of His attributes are created or contingent; however, the relation of the active attributes to the servant is contingent. The active attributes are under Allah's will (mashi’ah).
In any case, the aforementioned hadith is proof that Allah alone is the Owner of the hearts of the servants; He has the authority to turn them as and when He wills.
No one shares with Him in this attribute.
Nothing in the universe comes into existence without His will.
From this, it is also understood that the servant is in need of Allah at every moment; he can never be independent of Him, not even for a single instant. If he does not receive guidance and the ability to be guided (tawfiq al-hidayah) from Allah, he will be humiliated and disgraced in this world and will be seized with the severest punishment in the Hereafter. Despite this, the reality remains firm that the servant is endowed with will and responsibility (mukallaf), and reward or punishment on the Day of Judgment will be based on this will and choice.
(Sharh Kitab al-Tawhid lil-Ghunayman: 1/214)

Explanation:
1:
In this hadith, the manner and method of the Messenger of Allah (sallallahu alayhi wa sallam) swearing an oath is described: if the matter under discussion was not correct, he (sallallahu alayhi wa sallam) would first negate and reject it with the word "la" (no),
then he would swear an oath by one of Allah's attributive names,
from this it is also understood that it is permissible to swear an oath by Allah's attributive names.

Benefits and Issues:
➊ Swearing an oath by the attributes of Allah, the Mighty and Majestic, is the essence of tawhid (monotheism).
➋ Placing "la" (no) at the beginning of an oath is a well-known style in the Arabic language.

(1) "La" is a negation of the preceding statement. It is as if this oath is being taken to negate a certain statement. It is possible that it has come solely for emphasis, just as in: ﴿La uqsimu bi-yawm al-qiyamah﴾ (Al-Qiyamah: 75:1). In this case, it will be considered superfluous, meaning it will not be translated, but emphasis will still be achieved.

(2) It is recommended (mustahabb) to swear an oath with these words.

(3) It is permissible to swear an oath by the actions of Allah, the Exalted.

(4) According to the preferred opinion, this narration is authentic due to supporting evidence, as the researcher of the book has also stated that the preceding hadith suffices for this.

(1) The relevance of these words is that remaining firm upon an oath depends on the strength and steadfastness of the heart, and hearts are in the grasp of Allah Ta'ala. It is as if, along with taking an oath, this is also a supplication that Allah Ta'ala keeps my heart steadfast.

(2) It is understood from this that whether the name of Allah is mentioned in the oath or any one of the specific attributes of Allah Ta'ala, both are equal.

Benefit:
The aforementioned narration has been declared weak in its chain of transmission by our esteemed researcher, whereas other scholars have graded it as authentic (sahih) and good (hasan). Furthermore, in Sahih al-Bukhari, the wording narrated from Abdullah ibn Umar radi Allahu anhu is «لَا وَمُقَلِّبِ الْقُلُوبِ» instead of «لَا وَمُصَرِّفِ الْقُلُوبِ».
Therefore, it is permissible to swear an oath using these words.
For details, see: (al-Sahihah, no. 2090, and Sunan Ibn Majah, edited by Dr. Bashar Awwad, hadith: 2092)

Takhrij:
«أخرجه البخاري، الأيمان والنذور، باب كيف كانت يمين النبي صلي الله عليه وسلم، حديث:6628.»©Explanation:
In this hadith, the manner and style of the Messenger of Allah (sallallahu alayhi wa sallam) when taking an oath is described: if the ongoing conversation or statement was not correct, he would first refute and negate it with the word "la" (no), then swear an oath by one of Allah’s attributive names.

From this, it is understood that it is permissible to swear an oath by the Most High Attributes of Allah, whether that attribute pertains to Allah’s essence, such as knowledge (‘ilm) and power (qudrah), or is an attribute of action, such as subjugation (qahr) and dominance (ghalabah), etc.