Lack of human strength may have a number of causes. Believers should be caring and compassionate towards the weak.
Causes of human physical weakness
See also
Sin
Divine action
Through wrestling with God, Jacob carried a physical reminder for the rest of his life.
Disobedience
Satanic action
Disease or disability
Weakness from birth
Weakness in old age
Persecution
The physical weakness of Jesus Christ after flogging led to Simon carrying the cross
Weakness and fear are often associated
Being faced with opposition
Corporate weakness
Believers' responsibility to the weak
The weakness of God