He is the one whose knowledge encompasses all the outward and hidden matters, the open and secret, all those things that must necessarily occur, all those things that are impossible to occur and all those things that can possibly occur. He knows the affairs of the whole of creation, of the past, the present and the future. There is absolutely nothing that is hidden from Him.
“Verily Allah [alone] has the knowledge of the Hour, He sends down the rain and knows what is in the wombs. No soul knows what it will earn tomorrow and no soul knows in what land it will die. Indeed Allah is 'Alim, Khabir.”
[Luqman (31): 34]
“O Mankind! We have created you from a male and a female and made you into nations and tribes that you may know each other. Verily, the most noble of you in the Sight of Allah is the most pious and God-Fearing of you. Indeed Allah is 'Alim, Khabir.”
[al-Hujurat (49): 13]
From “Explanation to the Beautiful and Perfect Names of Allah” — Shaykh as-Sa’di (d.1376H)