“Casting all your care upon Him, for He cares for you.”
The Christian is to cast his anxieties “upon Him” — the Lord. This trust in God means no heartache, difficulty, or problem is too difficult for the plan of God. No sin is too great for him to handle.
God is willing and able to carry any care we may face.
Unbelief is an exalting of self against God. We depend on ourselves rather than God. But why do we worry if we are his concern? God is infinitely more exercised about our welfare than we are. A child who asks his parents every day, “Can I be sure that you will take care of me?” ruins his well-being and breaks his parents’ hearts. The trusting child goes about his play undisturbed and assured of his mother’s love.