Surah Al-Kahf — Ayah 23 (18:23)
وَلَا تَقُولَنَّ لِشَاْيۡءٍ إِنِّي فَاعِلٞ ذَٰلِكَ غَدًا ٢٣
English translation (Saheeh International)
And never say of anything, "Indeed, I will do that tomorrow,"
Brief commentary
Do not say - O Prophet - about anything that you want to do tomorrow: “I am going to do this tomorrow,” because you do not know whether you will do it or you will be prevented from doing so? This is a directive for every Muslim.