Why do many Christians grow so slowly in their desire for spiritual things? The majority are content to remain in their present state and are only concerned not to lose the ground they have gained. This attitude brings shame upon the glory of true religion and deprives the soul of men of peace and comfort. Men have some reason to believe, or at least they hope and suppose that they have ‘passed from death to life’, that they are in a state of grace, and have been graciously accepted by God. This assurance they make every effort to keep alive by the diligent performance of religious duties and the avoidance of such sins by which they might forget salvation. But few make any real effort to thrive in this state, to grow in grace, to be changed from glory to glory into the image of Christ, to press towards the mark of the high calling of God in Christ Jesus, to lay hold of eternal life, to be more holy, more humble, more righteous, more spiritually minded, and to have their desires more and more transformed into the likeness of heavenly things. The spiritual state which they have reached satisfies the church and gives them a reputation for being religious, so they are quite satisfied. But to be more holy and heavenly, to have their hearts more and more taken up with heavenly things, they think to be inconsistent with their present state. So because of this foolishness, Christianity has lost much of its glory, and the souls of men have been deprived of the witness to the true power of godliness.
– John Own, Spiritual-Mindedness, pp. 192-193.