Why not despair?
The Islamic meaning of sabr is to stop ourselves from despairing and panicking, to stop our tongues from complaining, and to stop our hands from striking our faces and tearing our clothes at times of grief and stress.
To have _sabr_ is to first realize within your own heart that a) there is a god that exists b) that this god is worthy of all my worship c) that this god is indeed characterized by attributes of perfectness and majesty, which can only be ascribed to god and no other.
After having understood this, sabr is then to act upon this belief and not despair or panic because in your heart you know that there is a god that exists above the heavens and earth characterized by attributes of ultimate and complete mercy, love, care, wisdom, and knowledge (all in a matter that befit his majesty). You understand that this god, the one and only god–Allah–will always be there to help you through the tough times. You understand that anytime you need his aid all you have to do is ask; no need for intermediaries, just your own choice to raise those hands and ask Him. The essence of sabr is to realize this and not despair because you have with you Allah, the one who will never fail you.
Surah Baqarah V.284: To Allah belongs all that is in the heavens and all that is on the earth, and whether you disclose what is in your ownselves or conceal it, Allah will call you to account for it. Then He forgives whom He wills and punishes whom He wills. And Allah is Able to do all things.
Mankind only despairs and panicks at their own inability or the inability of others around them. You may lose a job tomorrow, have a car accident, or find a loved one has passed away and in this you will see reality. We as humans will naturally despair and panick because we recongize our own weaknesses. In that situation we recognize our limited ability to do anything and we see the same in the people around us. In these difficult situations we realize that sustenance was never something we controlled, we realize that we never had the slightest control over the occurances of the world, and we understand that matters of life and deaht are out of our hands. Undersatnding these fundamental, eye-opening, realities lead us to despair and panick because we realize our inability to control these situaions and we lose hope in finding a solution from those around us.
Surah Naml V.62: Is not He (better than your gods) Who responds to the distressed one, when he calls Him, and Who removes the evil, and makes you inheritors of the earth, generations after generations. Is there any ilah (god) with Allah? Little is that you remember!
However, for the one who believes in god, who understands Allah, they realize that even though they themselves don’t have the control, they can count on the one that has all the control. Thus, the one who secures his faith shows it in _sabr. _He_ _has no need to despair or panick because he isn’t dealing with incapable creatures, rather he is dealing with the most perfect, the one to whom all power and strength belong, the creator of all the creatures, Allah subhanahu wa ta’ala.