According to Osho, when you relax into your weakness and drop all musts, the very idea of being strong evaporates. In surrender and acceptance you stop fighting the river, become natural, spontaneous, and present. Joined with the Whole/Truth, borrowed strength appears effortlessly; apart, the ego feels weak. In let-go, you are neither weak nor strong; just being, at home, in celebration.
If you stop trying to be strong and just accept yourself, the struggle ends and life carries you, so you feel okay without proving anything.