We have each of us an individual work to do, to gird up the loins of our minds, to be sober, to watch unto prayer. The mind must be firmly controlled to dwell upon subjects that will strengthen the moral powers. The youth should begin early to cultivate correct habits of thought. We should discipline the mind to think in a healthful channel, and not permit it to dwell upon things that are evil. The psalmist exclaims, "Let the words of my mouth, and the meditation of my heart, be acceptable in thy sight, O Lord, my strength, and my redeemer" (Ps.19:14).
As God works upon the heart by His Holy Spirit, man must cooperate with Him. The thoughts must be bound about, restricted, withdrawn from branching out and contemplating things that will only weaken and defile the soul. The thoughts must be pure, the meditations of the heart must be clean, if the words of the mouth are to be words acceptable to heaven, and helpful to your associates. Christ said to the Pharisees, "O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh. A good man out of the good treasure of the heart bringeth forth good things: and an evil man out of the evil treasure bringeth forth evil things. But I say unto you, That every idle word that men shall speak, they shall give account thereof in the day of judgment. For by thy words thou shalt be justified, and by thy words thou shalt be condemned" (Matt. 12:34-37).
In the Sermon on the Mount, Christ presented before His disciples the far-reaching principles of the law of God. He taught His hearers that the law was transgressed by the thoughts before the evil desire was carried out in actual commission. We are under obligation to control our thoughts, and to bring them into subjection to the law of God.--Review and Herald, June 12, 1888. YRP 52
It was by the word of God that Christ overcame the wicked one. DA 257
Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things. Philippians 4:8 (King James Version)