god is the one who has created you in a state of weakness then he has granted you strength following weakness later on he has given you infirmity and grey hairs in place of strength. he creates whatever he wishes he is the all knowing and all powerful.
الله الذي خلقكم من ضعف ثم جعل من بعد ضعف قوة ثم جعل من بعد قوة ضعفا وشيبة يخلق ما يشاء وهو العليم القدير