"Man's heart, by nature, is not true. It is neither true to himself nor to God. In some respects it may be said to be true to himself and his fellow men, when it is true to his own interests and true to his usual character, or when it is true to the friendships and affections of earth. In the last of these respects we often hear of the heart's truth. We hear how truly hearts beat in affection for each other. We hear of friends being true to friends, so as to maintain their mutual constancy unshaken amid distance, suffering, and peril. But in all this, how seldom is it that we hear of hearts that are true to God and to Christ.
What is a true heart? It is not a perfect heart, for where is that to be found on earth? It is not a heart where sin has no place at all, and where all is holy and spiritual, for who, save the spirits of the just made perfect, have reached this stature? It is not a heart that never wavers, never saddens, never droops, never languishes, never grows cold, for that we must seek a brighter world and a more genial clime.
A true heart is one that has ceased to misunderstand and mistrust the character of God, that takes that character simply as it is revealed in grace, and rests where God would have the sinner to rest, on His forgiving love. A true heart is one that has ceased to suspect God or to look upon Him as an austere and hard master. The trueness of the heart consists in its right apprehensions of the character of God; in "knowing the Father" as He has made Himself known to sinners in Christ Jesus. To be true to God is to know Him as the gracious One, as the pardoning One, as the sin-hating, yet sinner-loving God. He who has not yet seen enough of Him in the Cross, as to dispel all his wicked doubts and guilty fears, is not yet true to God.
A false heart is one which does not know the Father. Its views of God’s character are distorted and dim. It seeks, in self-righteousness, to do something or feel something which may draw towards it the favor of God, and it cannot rest or trust without finding this. It does not understand the entire freeness of the grace revealed in Jesus…”
-By Horatius Bonar 1808-1899 Scotch Minister, Hymn Writer