Hadith: Indeed Allah, the Almighty, created His creation in darkness, then He cast His Light upon them, so whoever is touched by that light is guided, and whoever is not goes astray. It is for this reason that I say that the (ink of) the pen has dried upon the knowledge of Allah

عن عبد الله بن عمرو رضي الله عنهما قال: سمعت رسول الله صلى الله عليه وسلم يقول: «إنَّ اللهَ عزَّ وجلَّ خلق خَلْقَه في ظُلْمة، فألقى عليهم من نوره، فمَن أصابه مِن ذلك النور اهتدى، ومَن أخطأه ضلَّ»، فلذلك أقول: جَفَّ القلم على علم الله.
[صحيح] - [رواه الترمذي وأحمد]

‘Abdullāh ibn ‘Amr (may Allah be pleased with him) reported: I heard the Messenger of Allah (may Allah’s peace and blessings be upon him) saying: "Indeed Allah, the Almighty, created His creation in darkness, then He cast His Light upon them, so whoever is touched by that light is guided, and whoever is not goes astray. It is for this reason that I say that the (ink of) the pen has dried upon the knowledge of Allah."
[Authentic hadith] - [Narrated by At-Termedhy - Narrated by Ahmad]

Explanation

This Hadīth clarifies that Allah, the Almighty, created the creation in darkness and cast some of His light upon them. Those whom the light fell upon are the ones guided to the way to Paradise, and those whom the light missed are the ones who strayed from the way of truth. Guidance and misguidance are in total agreement with Allah's prior knowledge. That which has been decided eternally cannot change or be altered, and the expression about the drying of the ink of the pen indicates this fact.