“Let the words of my mouth, and the meditation of my heart, Be acceptable in Thy sight, O Lord, my Rock and my Redeemer.” (Ps. 19:14).
Since you have come into Christ, a change has taken place in your mind. Those outside of Christ have a “fleshly mind,” (Col. 2:18), a “blinded” mind (2 Cor. 4:4), and a “vain” mind, being darkened in their understanding.” Paul says, “alienated from the life of God, because of the ignorance that is in them, because of the hardening of their heart.” (Eph. 4:17-18) But a wondrous transformation has taken place now that you belong to Christ. “Wherefore if any man is in Christ, he is a new creature: the old things are passed away; behold, they are become new.” (2 Cor. 5:17)
You still have the same mental faculties, but now they are under a different control. “For the mind of the flesh is death; but the mind of the Spirit is life and peace.” (Rom. 8:6) You also have a part to play in this transformation. “Wherefore girding up the loins of your mind, be sober and set your hope perfectly on the grace that is to be brought unto you at the revelation of Jesus Christ.” (1 Pet. 1:13) You have a race to run and cannot afford to let your mind be cluttered with all of the mental trash that lies on every hand. The Christian must learn to concentrate his thoughts on the highest and the best. That which will not contribute to the reaching of you goal must be rejected. You cannot allow your mind to be an open garbage can, ready to receive anything that may come along.
“Finally, brethren, whatsoever things are true, whatsoever things are honorable, 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.” (Phil 4:8)
To guard your thinking, you must first guard your reading. There are too many good, inspiring, uplifting books and magazines available for you to waste your time and thought on that which is frivolous, trashy, or vile. It is not wrong for a Christian to keep up with current event so that he can better pray about world conditions and work more effectively for the advancement of the kingdom of God. However, you should not forget that you are a pilgrim here and that your primary interest should be centered on the things that are above (Col. 3:1-4). Through reading what other Christians have written, you profit by their experiences and the truths which they have gleaned from the Word of God. You can become acquainted with the saints of God all down through the centuries by reading their writings, and your own life will be the richer for having come to know them.