What do I do if I have committed sexual sin?

     Christians are not exempt from sexual sin.  If you are such a person who has fallen into fornication, adultery, pornography, homosexuality, lesbianism, bestiality, or any other sexual deviation, then you need to stop.  You need to confess your sins to the Lord and break off your relationships that lead you or tempt you into further sin.  This may be hard to hear, but it is what is necessary.
     The sexual drive is a very powerful one.  It is so strong that it can alter a person's thinking and emotions.  It can harden the heart and move us to irrational and sinful decisions.  God has created sex for the marriage bed and for there alone.  He wants you to be pure in mind and body, reserving the sexual union for the proper context of marriage so that you might properly honor God and your spouse.  Failure to do this is to commit grievous sin.  But all is not lost.

There is forgiveness in Christ

     All of your sexual sin can be forgiven.  The blood of Christ is too great to be defeated by your sin.  Jesus paid a great price on the cross (1 Pet. 2:24).  He shed His blood and gave His life and if you are a Christian, then you have been bought with a great price.  You are not your own and the Lord always longs to fellowship with you (1 Cor. 1:9).  All you need to know is that you must confess your sin to God and repent of it.  This means you stop doing it.  You are called by God to purity, not to sexual immorality.

• 1 Cor. 6:18, "Flee immorality. Every other sin that a man commits is outside the body, but the immoral man sins against his own body."
• Eph. 5:3, "But do not let immorality or any impurity or greed even be named among you, as is proper among saints." 
• Col. 3:5, "Therefore consider the members of your earthly body as dead to immorality, impurity, passion, evil desire, and greed, which amounts to idolatry."
• 1 Thess. 4:2,  "For you know what commandments we gave you by the authority of the Lord Jesus. ³ For this is the will of God, your sanctification; that is, that you abstain from sexual immorality; ⁴ that each of you know how to possess his own vessel in sanctification and honor, ⁵ not in lustful passion, like the Gentiles who do not know God."

    The Greek word for "immorality" is porneia which means illicit sexual intercourse, i.e., fornication, homosexuality, lesbianism, bestiality, etc.  The English word "pornography" is derived from this Greek word.  So, you can see that God desires your holiness.  After all, this is why you are a Christian, to honor God, glorify Him, and live for Him.
    To repeat, if you are in sexual sin, stop it, confess it, break off tempting relationships and situations, and seek the Lord.  If you fall again, then go to the cross again.  Never give up going to Jesus and receiving the forgiveness that you need.  Never think that the Lord Jesus will stop loving you.  Never doubt Him.  He loves you and knows your struggle. 
    Then, after you have repented, see if you can find someone to be accountable to.  Find someone trustworthy and have them pray with you regularly.  It is so true that sometimes beating sexual sin cannot be done alone.  Sometimes we need the strength of the body of Christ.

What if I don't repent of my sin?

     If you are a Christian involved in sexual sin then you know that the Holy Spirit has been convicting you.  If you feel no conviction then you are either not really saved or are so hardened by the sin you've been committing that you are close to God taking your life.  This is the case in 1 Cor. 5:5 where a man was having sex with his father's wife and he would not repent.  Paul said, "I have decided to deliver such a one to Satan for the destruction of his flesh, that his spirit may be saved in the day of the Lord Jesus."  Rest assured that God takes this seriously.  He will take your life to essentially save your soul.  This is a loving  move on God's part.
    If you are reading this, then the Lord has directed you here because He wants you to know about this issue.  If you are in such sin, you know what the Lord requires of you.  If you are not in this sin, then thank the Lord for His mercy and continue to seek the Holiness of the Lord. ---Matthew Slick "CARM" http://www.carm.org.