Only spiritual things are eternal and real. All inharmonies and seeming limitations in the world are the result of man's error beliefs and thoughts, and man can eliminate them by eliminating error from his mind. He can do this by understanding that God's creation is all that there is, and knowing it to be good. In this way divine ideals are established in mind, and by the law of mind action they are expressed, thus bringing into manifestation the perfection that ever exists in the ideal.
The law of mind action may be described in three steps: mind, idea, manifestation. First, there must be mind; second, everything exists first as an idea in mind; third, the inherent power and intelligence in the idea causes it to act or express, and when it is expressed we have the manifestation. (See CREATION.)
To serve the Lord is to keep the divine law, the law of right thought. It has come to be recognized as a law of mind action that men become like that which they behold; they manifest that which they mentally see. One who knew this law wrote, "Nothing foretells futurity like the thoughts over which we brood."
The "heart" is the subconsciousness of man. The laws of Jehovah are written on the heart by man's meditating on and realizing spiritual ideas as the reality of his being. (See Deut. 6:6-9; Heb. 8:10; 10:16.)