Praise be to Allah, and may peace and blessings be upon the Messenger of Allah.
First, it is important to distinguish between the matter of the Names and Attributes of Allah and the matter of statements used to report about Him. The Names of Allah are tawqifiyyah, meaning that a Name may only be affirmed for Him on the basis of evidence from the Qur’an or Sunnah. As for reporting about Him, this category is broader. It is permissible to report about Allah using terms that were not transmitted as Names, provided that their meaning is correct and does not imply any deficiency or disrespect.
The scholars have established that Allah may only be invoked by His Beautiful Names, whereas when reporting about Him, expressions with correct meanings may be used, such as “existing,” “Essence,” and similar terms.
The Arabic term “kā’in” linguistically indicates existence and actuality. If what is intended by it is that Allah تعالى exists eternally and forever, that His existence was not preceded by non-existence and will not be followed by annihilation, then there is no harm in reporting about Him using this term, because the meaning is correct and contains no deficiency.
It is established in the hadith:
“Allah was, and there was nothing before Him, and His Throne was upon the water, then He created the heavens and the earth...” Narrated by al-Bukhari.
It is also reported in some narrations: “Allah was, and there was nothing other than Him,” and in another narration: “There was nothing with Him.”
This indicates that Allah سبحانه is the First, before whom there was nothing, and that He is the Everlasting, who does not perish.
Allah تعالى says:
﴿Everything will perish except His Face. His is the judgment, and to Him you will be returned.﴾ [Al-Qasas: 88]
And He سبحانه says:
﴿Everyone upon it will perish, and there will remain the Face of your Lord, Possessor of Majesty and Honor.﴾ [Ar-Rahman: 26–27]
It is also authentically reported that the Prophet صلى الله عليه وسلم said in his supplication:
“You are the Ever-Living who never dies, while the jinn and human beings die.” Narrated by Muslim.
Therefore, if by the statement “Allah is kā’in” the speaker means that He exists, that His existence was not preceded by non-existence and will not be followed by annihilation, then it is permissible to report this about Him in terms of meaning.
The permissibility of reporting about Allah تعالى using a certain term does not necessarily mean that the term is one of His Beautiful Names.
The category of Names is based strictly on revelation. Allah may only be named with what is established in the Qur’an and Sunnah, whereas the category of reporting about Him is broader.
Therefore, the more precise statement is: It is permissible to report about Allah تعالى that He is kā’in, meaning that He exists and remains forever; however, “Al-Kā’in” should not be declared one of the Beautiful Names of Allah unless there is a revealed proof establishing it as such.
With regard to terms that have not been mentioned in the revealed texts, consideration is given to the meaning they convey.
If a term indicates a correct meaning that befits Allah تعالى, it may be used when there is a need to report about Him. But if it contains a corrupt meaning, a deficiency, or gives such an impression, it is not permissible to use it.
When clear revealed expressions are available, it is preferable to use them, such as:
“Allah تعالى exists; He is the First, before whom there was nothing, and the Last, after whom there will be nothing; and He is the Ever-Living who never dies.”
It is permissible to report about Allah تعالى as “kā’in” if what is meant is that He exists eternally and forever, before everything and after everything, and that He does not perish.
However, it is not correct to make “Al-Kā’in” one of the Beautiful Names of Allah merely because it is permissible to report about Him using this term, because the category of reporting is broader than the category of Names and Attributes.
And Allah تعالى knows best.