[W]e may see what wisdom is required in the guiding and management of our hearts and ways before God. Where the subjects of a ruler are in feuds and oppositions one against another, unless great wisdom be used in the government of the whole, all things will quickly be ruinous in that state. There are these contrary principles in the hearts of believers. And if they labor not to be spiritually wise, how shall they be able to steer their course aright? Many men live in the dark to themselves all their days; whatever else they know, they know not themselves. They know their outward estates, how rich they are, and the condition of their bodies as to health and sickness they are careful to examine; but as to their inward man, and their principles as to God and eternity, they know little or nothing of themselves. Indeed, few labor to grow wise in this matter, few study themselves as they ought, are acquainted with the evils of their own hearts as they ought; on which yet the whole course of their obedience, and consequently of their eternal condition, doth depend. This, therefore, is our wisdom; and it is a needful wisdom, if we have any design to please God, or to avoid that which is a provocation to the eyes of his glory. John Owen, Remainders of Indwelling Sin in Believers, Chapter One.