Weakness
"So let man see from what he is created! He is created from a water gushing forth, proceeding from between the backbone and the ribs. Verily, (Allah) is able to bring him back (to life)! The Day when all the secrets (deeds, prayers, fasting) will be examined (as to their truth). Then he will have no power, nor any helper." (Qur'an: Translation of the meaning, 86: 5-10)
A human being is a creature who cannot relive himself or cause it any harm unless Allah wills. He cannot have any effect on his own life or death or resurrection. Without the Mercy of Allah none could live upon the earth beside the great forces of different nature one may encounter, like, beasts, insects, germs and many others only Allah knows.
A human being is created from a drop of semen and when he grows, a thorn, a sting, or a wound can easily cause him sleeplessness. Any harm fated for him may cause his end and a germ may cause his weakness or perhaps death, If a house fly takes something away from him he cannot get it back from this weak creature.
"...And if the fly snatches away a thing from them, they will have no power to release it from the fly, so weak are (both) the seeker and the sought."
(Qur'an: Translation of the meaning, 22:73)