Just as our sustenance, down to the last morsel, has been decreed long before our birth, our life, down to the last breath, has been similarly decreed. Hence, we have a limited amount of breaths to take, and, with every breath, we draw nearer and nearer to our death.

Sayyiduna ‘Ali (radhiyallahu ‘anhu) has described the reality of death and our limited breath in the following verses:

حَيَاتُكَ أَنْفَاسٌ تُعَدُّ فَكُلَّمَا            مَضَى نَفَسٌ أَنْقَضَتْ مِنْ عُمُرِهَا جُزْءًا

The years of your life are but counted breaths. Every breath that passes decreases a portion from your life.

وَيُحْيِيْكَ مَا يُفْنِيْكَ فِيْ كُلِّ حَالَةْ       وَيَحْدُوْكَ حَادٍ مَا يُرِيْدُ بِكَ الْهُزْءَ

That which is slowly leading to your death is also sustaining you at every moment (i.e. your breathing), and it acts as one driving you with complete seriousness (to your death).

فَتُصْبِحُ فِيْ نَفَسٍ وَتُمْسِيْ بِغَيْرِهَا                 وَمَا لَكَ مِنْ عَقْلٍ تُحِسُّ بِهِ رُزْءً

You awake in the morning with one breath, and you enter the evening with another, and your intelligence cannot perceive when these breaths will abruptly cease.

(The Poetic Works of Sayyiduna ‘Ali [radhiyallahu ‘anhu] pg. 7)