﴿ وَمَا كَانَ لِنَفْسٍ أَن تَمُوتَ إِلَّا بِإِذْنِ ٱللَّهِ كِتَٰبًۭا مُّؤَجَّلًۭا ۗ وَمَن يُرِدْ ثَوَابَ ٱلدُّنْيَا نُؤْتِهِۦ مِنْهَا وَمَن يُرِدْ ثَوَابَ ٱلْءَاخِرَةِ نُؤْتِهِۦ مِنْهَا ۚ وَسَنَجْزِى ٱلشَّٰكِرِينَ ﴾

“And no human being can die save by God's leave, at a term pre-ordained. And if one desires the rewards of this world, We shall grant him thereof; and if one desires the rewards of the life to come, We shall grant him thereof; and We shall requite those who are grateful [to Us].”

It is not for any soul to die, save by the leave of God, a prescribed term, and so the one who has certainty shall witness the meaning of this and find himself the most valiant of men, as Ḥātim b. al-Aṣamm related of himself in what he witnessed with Shaqīq al-Balkhī, may God have mercy on both, in one of the campaigns into Khurāsān. He relates, 'Shaqīq found me as the battle was raging. He asked me, �How do you find your heart O Ḥātimḍ�. I replied, �Like on my wedding night, [wavering] between two states�. He then put down his weapons, saying, �As for me, mine is like this�, and laid his head down on his shield. He slept [so deeply] as the battle raged, you could hear him snoring. That is the ultimate in terms of the heart being reassured by God and its confidence in Him by virtue of the strength of its certainty.