the danger of masturbation

“That every one of you should know how to possess his vessel in sanctification and honour; Not in the lust of concupiscence, even as the Gentiles which know not God:”

(1 Thessalonians 4:4-5, King James Version)

It is from these very words above (of the apostle Paul) that advice may be taken to further explain a matter which according to some, the Bible apparently makes no reference - that of undisclosed and unaccompanied indulgence, or quite simply masturbation. Self-gratification like with masturbation carries with it the desire to rebel against God's authority over our own bodies. It consists of making sexual experiences an end to be desired, and sought after for its own sake. Then from there, a man or woman becomes a servant to his or her own desires, instead of mastering them once and for all.
Masturbation may not lead to contracting a sexually transmitted disease as would fornication, but it has the ability to enable birth pangs (depression) in your spirit, a sense of guilt and a weakening of willpower — all of which finally robs a person of his or her fellowship with God and his or her spiritual effectiveness. If indulged in excessively, it can also cause problems in the sexual relationship that comes only after marriage. If you ask me, masturbation is a sin because it is an abuse of God's gift of sex, being distorted and disproportioned to gratify our lusts. It must be repented of and forsaken immediately.
So often is it because of young people learning the “facts” of sex in the most perverted and twisted form from their worldly friends, which makes them more susceptible to be caught up in the grip of this evil habit. Once this habit is indulged in, it grips the person so strongly that he is compelled to yield to it again and again and again. But Christ can set him free.
Above all else, we should always practice being in the presence of the Lord at all times — being conscious of the fact that the Lord is always with us and watching us. We would obviously not indulge in masturbation if another believer were observing us. How much more should we fear God! Remember, it is better to go into life maimed than have our whole body casted into Hell. He who the Son has set free is free indeed. Be free, my friend!
“Ye have heard that it was said by them of old time, Thou shalt not commit adultery: But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart. And if thy right eye offend thee, pluck it out, and cast it from thee: for it is profitable for thee that one of thy members should perish, and not that thy whole body should be cast into hell. And if thy right hand offend thee, cut it off, and cast it from thee: for it is profitable for thee that one of thy members should perish, and not that thy whole body should be cast into hell. It hath been said, Whosoever shall put away his wife, let him give her a writing of divorcement: But I say unto you, That whosoever shall put away his wife, saving for the cause of fornication, causeth her to commit adultery: and whosoever shall marry her that is divorced committeth adultery.”

(Matthew 5:27-32, King James Version)