2 Peter 3:18

But grow in grace — That is, in every Christian temper. There may be, for a time, grace without growth; as there may be natural life without growth. But such sickly life, of soul or body, will end in death, and every day draw nigher to it. Health is the means of both natural and spiritual growth. If the remaining evil of our fallen nature be not daily mortified, it will, like an evil humour in the body, destroy the whole man. But "if ye through the Spirit do mortify the deeds of the body," (only so far as we do this,) "ye shall live" the life of faith, holiness, happiness. The end and design of grace being purchased and bestowed on us, is to destroy the image of the earthy, and restore us to that of the heavenly. And so far as it does this, it truly profits us; and also makes way for more of the heavenly gift, that we may at last be filled with all the fulness of God. The strength and well — being of a Christian depend on what his soul feeds on, as the health of the body depends on whatever we make our daily food. If we feed on what is according to our nature, we grow; if not, we pine away and die. The soul is of the nature of God, and nothing but what is according to his holiness can agree with it. Sin, of every kind, starves the soul, and makes it consume away. Let us not try to invert the order of God in his new creation: we shall only deceive ourselves. It is easy to forsake the will of God, and follow our own; but this will bring leanness into the soul. It is easy to satisfy ourselves without being possessed of the holiness and happiness of the gospel. It is easy to call these frames and feelings, and then to oppose faith to one and Christ to the other. Frames (allowing the expression) are no other than heavenly tempers, "the mind that was in Christ." Feelings are the divine consolations of the Holy Ghost shed abroad in the heart of him that truly believes. And wherever faith is, and wherever Christ is, there are these blessed frames and feelings. If they are not in us, it is a sure sign that though the wilderness became a pool, the pool is become a wilderness again. And in the knowledge of Christ — That is, in faith, the root of all. To him be the glory to the day of eternity — An expression naturally flowing from that sense which the apostle had felt in his soul throughout this whole chapter. Eternity is a day without night, without interruption, without end.