Praise be to Allah, and peace and blessings be upon the Messenger of Allah. To proceed:
Justice is established for Allah Almighty, and it is one of His essential attributes, because Allah has always been and will always remain characterized by justice. He is just and equitable, and He possesses perfect justice and fairness eternally and forever.
Allah’s justice is established in the Sunnah. In the two Sahih collections, al-Bukhari (3150) and Muslim (1062), in the hadith of ‘Abdullah ibn Mas‘ud, may Allah be pleased with him, concerning the man who objected to the Prophet’s ﷺ distribution, he said:
“Then who will act justly if Allah and His Messenger do not act justly?”
This hadith indicates that justice is established for Allah Almighty and that He does not wrong or act unjustly.
Allah Almighty also described His words as being just, saying:
{And the word of your Lord has been fulfilled in truth and justice}
[Al-An‘am: 115]
Meaning that Allah’s words are complete in both truthfulness and justice.
Also related to this meaning is what was reported from Mu‘adh ibn Jabal, may Allah be pleased with him, that whenever he sat in a gathering of remembrance, he would say: “Allah is a Judge, perfectly just; those who doubt have perished...” This was narrated by Abu Dawud (4611) as a statement of Mu‘adh and authenticated by al-Albani. The expression “Judge, perfectly just” was explained as meaning “a just Judge.”
The divine attributes are divided, with regard to their connection to Allah’s Essence, into essential attributes and attributes of action.
An essential attribute is an attribute with which Allah has always been and will always remain characterized, and which is never separate from His Essence.
Shaykh Ibn ‘Uthaymin, may Allah have mercy on him, said in defining the essential attributes:
“The essential attributes are attributes of meaning that are eternally and permanently established for Allah, such as life, knowledge, power, hearing, sight, might, and wisdom.”
Based on this principle, justice is an essential attribute of Allah Almighty because Allah has always been and will always remain characterized by justice. His justice is not something newly occurring, nor is it an attribute that He possesses at one time and not at another.
For this reason, Ibn al-Qayyim, may Allah have mercy on him, said:
“Justice is among His attributes in His actions,
His speech, His judgment, and the balance.”
Thus, justice is established for Allah Almighty in His actions, rulings, and words.
It is important to distinguish between affirming the attribute of justice for Allah Almighty and the question of calling Him by the Name “Al-‘Adl” or “Al-Muqsit.”
Establishing an attribute is one matter, while establishing a particular Name is another. An attribute may be established for Allah by evidence, while scholars may still differ regarding whether a specific Name may be derived and applied to Him on that basis.
There has been scholarly disagreement regarding naming Allah Almighty “Al-‘Adl” and “Al-Muqsit.” This is a separate issue from the fundamental affirmation of the attribute of justice for Allah Almighty.
Therefore, disagreement regarding the Name should not be used as a reason to deny the established attribute.
The attribute of justice is established for Allah Almighty, and it is one of His essential attributes, because Allah has always been and will always remain characterized by justice. He does not wrong or act unjustly; rather, His actions, rulings, and words are founded upon perfect justice.
As for applying the Name “Al-‘Adl” or “Al-Muqsit” to Allah Almighty, that is a separate discussion related to establishing the Beautiful Names, and scholars have differed regarding it.
And Allah knows best.