The use of means for the obtaining of peace is ours; the bestowing of it is God’s prerogative.
The privileges of our adoption made known to our souls are the ways instituted by God to give us life, vigour, courage, and consolation. “The Spirit bearing witness with our spirits that we are the children of God,” giving us a new name and a white stone, adoption and justification, that is, as to the sense and knowledge of them, the immediate cause is the Spirit.
But this I say, in our ordinary walking with God, and in an ordinary course of his
dealing with us, the vigour and comfort of our spiritual lives depend much on our mortification, because this alone keeps sin from depriving us of the one and the other.
Every unmortified sin will certainly do two things:
[1.] It will weaken the soul, and deprive it of its vigour.
[2.] It will darken the soul, and deprive it of its comfort and peace.
[1.] It weakens the soul, and deprives it of its strength. When David had for a while harboured an unmortified lust in his heart, it broke all his bones, and left him no spiritual strength; hence he complained that he was sick, weak, wounded, faint. “There is,” saith he, “no soundness in me,” Ps. 38:3; “I am feeble and sore broken,” verse 8; “yea, I cannot so much as look up,” Ps. 40:12. An unmortified lust will drink up the spirit, and all the vigour of the soul, and weaken it for all duties.
Because it entangles the affections. It diverts the heart from the spiritual frame that is required for vigorous communion with God; it lays hold on the affections (lusts), rendering its object beloved and desirable, so expelling the love of the Father, 1 John. 2:15, 3:17; so that the soul cannot say uprightly and truly to God, “You art my portion,” having something else that it loves. Fear, desire, hope, which are the choice affections of the soul, that should be full of God, will be one way or other entangled with this unmortified lust.
It fills the thoughts with schemes as to how to satisfy the lust, so the imagination is defiled.
As sin weakens, so it darkens the soul. It is a cloud, a thick
cloud, that spreads itself over the face of the soul, and intercepts
all the beams of God’s love and favour. It takes away all sense of the
privilege of our adoption;