Eternality is necessary for Allah, meaning having no beginning. When referring to Allah [the term] Qidam does not mean a long period of time that lapsed. The expressions Qadim and Azaliyy, if used in reference to Allah, mean that Allah has no beginning for His Existence. Thus it is said that Allah is Azaliyy and Allah is Qadim. If they were used in reference to the creation, then they would have the meaning of an extended lapse of time. Allah the Exalted Said about the moon:
﴿حَتَّى عَادَ كَالعُرْجُونِ القَدِيمِ﴾
[which means] “…until it returns back to the stage that resembles the old [qadim] palm branch.”
The author of Al-Qamus, Al-Fayruz’abadiyy, said, “The Pyramids are two ancient [Azaliyy] buildings in Egypt.”
The evidence of His Eternality, the Exalted, is that had He not been Eternal, it would be necessary that He have a beginning. Then He would be in need of someone to give Him a beginning, and had He been in need of someone to give Him a beginning, that would lead to circular causation or to the claim of [a chain of] beginningless events, and both are impossible. It is confirmed that it is impossible for Allah to have a beginning, hence His Eternality is confirmed.