All the spiritual might and strength that a Christian has, he has it from the Holy Spirit. Though the Spirit strengthens every Christian in the inner man, yet I do not say that the Spirit strengthens every Christian alike in the inward man. Some have stronger corruptions to subdue than others, and more violent temptations to withstand than others, and greater difficulties to wrestle with than others, and choicer mercies to improve than others, and higher and harder duties of religion to manage than others, and accordingly they are more strengthened in the inner man than others.
– Thomas Brooks –
from The Secret Key To Heaven, 1665