I found this very thought provoking.
Men may believe they possess the true spirit of Godliness and yet not possess it. They may suppose that Godliness consists in something which falls far short of true Godliness, and even if they suppose it to consist in that which the Scriptures represent it to consist, they may not possess it.
There is a love, a repentance, a faith, a hope, a joy, a self-denial, which are of mere human origin and spurious. The religious affections of many men are founded in supreme selfishness. They are willing to love and serve God just so far as they believe He is willing to love and serve them, and no farther, and this is “making him to serve with their sins” (Isa. 43:24).
The religion of such men consists in being very anxious about their own welfare, but very little concerned for the honor and glory of God. It is easy to say, “Pardon is mine; grace is mine; Christ and all His blessings are mine; God has freely loved me; Christ has graciously died for me; and the Holy Spirit will assuredly sanctify me in the belief of these precious truths.” It is no Herculean task for an ardent mind and an unsanctified, enthusiastic heart, to make these discoveries. This is a kind of confidence which the subtle deceiver is interested to cherish.
And the joys and sorrows, the zeal and devotion, which spring from this delusion, constitute a sort of religion which the blindness and deceit, the self-flattery and pride of the carnal heart very easily substitute for true Godliness.
And what if a man firmly believes he will be saved? What if he imagines he has the assistance of the Spirit of God in “working out this faith in himself ”? The faith of the Gospel does not consist in "believing that one shall be saved"..
There is a difference between true saving faith in Jesus Christ and believing that we shall be saved.
Author Unknown - Puritan Gems