The Heart and its Deceitfulness
David would never have fallen into gross outward sin, had he not been too familiar with it in his heart; there had the evil been oft-times committed before it broke out in the wicked deed. Nor would he have numbered the people, had he not first strayed from the presence of God, and so become puffed up with pride. (2 Sam. 111; 1 Chron. 212)
Saints rarely see the guilt of a murmuring, unbelieving spirit, while they do feel the discomfort and weakness it brings with it. How great the deceitfulness of sin that can hide such guilt from the conscience of a child of God.
The Lord would have us all deal truly with our state, and with our hearts. We cannot otherwise deal truly with Him.
When we desire any special guidance, let us look first at the state of our heart: we have natural reason; let us take heed that we put it not into the hands of the devil by self-will, but into the hands of God.
The mistake of ignorance is one thing; the darkness of self-will is another. There may be the former though the eye be single, but not the latter.
It is good for a child of God to search his heart, that he may know whether it is by nature or by grace that he is kept from outward evil. Fear of shame, love of reputation, power of conscience, natural affection, self-interest, greatly preserve the unregenerate from the commission of sin; and may in part also keep the children of God from defiling their garments; but it is only by the power of grace, and when the heart keeps the life, that our “good conversation” is a sweet savour to God.
The great outlet of sin is the tongue; the great inlets of temptation are the ear and eye; but of the whole body the heart is mistress. Therefore let grace rule the heart, and the whole man shall be subject.