Every young person is sooner or later tempted by unclean thoughts. The sexual urge being stronger and more aggressive in men than in women, the former face this problem much more than the latter do. In Mark 7:21, Jesus listed evil thoughts as the first things that proceed from the heart of men. The hearts of all unconverted men are equally wicked and so the description Jesus gave is true of all. Unclean thoughts plague the mind of the morally upright man as much as they do the mind of the adulterer - even though lack of opportunity and fear of society may have prevented the former from committing adultery in the flesh.
Lustful thinking, once indulged in, will make a person more and more its slave. Deliverance becomes increasingly difficult with the passage of time. The sooner we seek for deliverance the easier it will be. Victory over evil thoughts (like victory over all other sin) comes through an honest confession of failure, a real longing for deliverance, an acceptance of the fact of our death with Christ, and an utter yieldedness of our bodies and minds to the Lord (Rom. 6.1-14).
We must also "walk in the Spirit" and cooperate with Him in disciplining our lives, if we are to enjoy continuous victory (Gal. 5.16-19). If we fail to discipline our eyes and ears (cutting off all reading and seeing and hearing that is lustful), we shall not be able to discipline our thoughts either (this is the real implication of Matt.5:28-30). Discipline of the body is essential for deliverance from lustful thoughts. The greatest of saints have confessed that they had to battle constantly with sexual temptations in their minds. They had to discipline their bodies severely in order to get victory.
Job, though a married man with ten children, recognized that if he was to be delivered from lustful thinking, he had to control his eyes. He said, "I made a covenant with my eyes not to look with lust upon a girl" (Job 31:1-LW). For men, the greatest temptations come through the eyes. If care is not exercised here and an unclean thought or picture is once allowed to enter our minds through the eye-gate, it becomes almost impossible to remove it from there.
We must fill our minds with the Word of God - for saturating our minds thus with God's Word is one of the surest safeguards against evil thinking. David said, "I have thought much about Your words, and stored them in my heart so that they would hold me back from sin" (Psa. 119:11-LW). The Bible also says, "If you value the approval of God, fix your minds on the things which are holy and right and pure and beautiful and good" (Phil. 4:8 -JBP).
Some may say that the prevailing standard of morals in the world around us is so low that it is difficult to be totally free from unclean thoughts. But this state of affairs is not peculiar to the twentieth century. Corinth in the first century was a centre of licentiousness and immorality, yet the Spirit of God urged the Christians there to lead their every thought captive into the obedience of Christ (2 Cor.10:5). He tells us to do the same today. The way to life may be narrow and difficult, but the Holy Spirit can strengthen us to walk that way.
To discipline our lives thus, does not mean that we should develop a repugnance for the opposite sex. Far from it! The fact that we find the opposite sex attractive is, in itself, not sinful. It is quite natural. It is not wrong for us to admire a pretty face as a part of God's beautiful creation. But being fallen creatures, if we are not careful, we shall soon begin to notice the beautiful form and then to lust. Thus the attractiveness of the opposite sex, though clean in itself, can become for us, an occasion for unclean thinking. Our safety lies in instantly obeying the voice of the Holy Spirit within us, when He checks us and tells us to turn our eyes and our thoughts in another direction.
