Blessed are the pure in heart,
   for they will see God.
- Matthew 5:8

Put to death therefore what is earthly in you: sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry.
- Colossians 3:5

Finally, brothers, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence, if there is anything worthy of praise, think about these things.
- Philippians 4:8

How can a young person stay on the path of purity?
   By living according to your word.
I seek you with all my heart;
   do not let me stray from your commands.
I have hidden your word in my heart
   that I might not sin against you.
- Psalm 119:9-11

And if we’re talking specifically about sexual purity (and impurity):

“I have the right to do anything,” you say—but not everything is beneficial. “I have the right to do anything”—but I will not be mastered by anything. You say, “Food for the stomach and the stomach for food, and God will destroy them both.” The body, however, is not meant for sexual immorality but for the Lord, and the Lord for the body. By his power God raised the Lord from the dead, and he will raise us also. Do you not know that your bodies are members of Christ himself? Shall I then take the members of Christ and unite them with a prostitute? Never! Do you not know that he who unites himself with a prostitute is one with her in body? For it is said, “The two will become one flesh.” But whoever is united with the Lord is one with him in spirit. Flee from sexual immorality. All other sins a person commits are outside the body, but whoever sins sexually, sins against their own body. Do you not know that your bodies are temples of the Holy Spirit, who is in you, whom you have received from God? You are not your own; you were bought at a price. Therefore honor God with your bodies.
- 1 Corinthians 6:12-20

Let marriage be held in honor among all, and let the marriage bed be undefiled, for God will judge the sexually immoral and adulterous.
- Hebrews 13:4

But I say to you that everyone who looks at a woman with lustful intent has already committed adultery with her in his heart.
- Matthew 5:28

I think most people struggle with sexual immorality, regardless of whether or not they’re in a relationship!

I am giving Him thanks that you really want to change that pattern of lust and sin. I think there are definitely steps you can take to help.

• Pray about it. Lift it up to the Lord and ask Him to change your hearts. Trust that the Lord will bless you if you let Him, because Jesus tells us in Matthew 7:7-11 that our Heavenly Father loves to give good gifts to His children.
• Both of you need to find an accountability partner who is a mature Christian of your own sex, and who will be able to support you as you fight lust without it being a stumbling block to them. I keep accountable to both female friends my age, and married women. Be honest with them and tell them specifically how you are struggling. Bring the sin out into the light and watch it shrivel up, or it’ll fester in the darkness. James 5:6 instructs us to confess your sins to each other and pray for each other so that you may be healed. The prayer of a righteous person is powerful and effective.
• Set appropriate boundaries. Sometimes things that aren’t wrong in themselves necessarily (kissing while lying down, for example) can trigger lust and God is glorified when we decide that purity is worth giving up these things. Sit down together and come up with specific guidelines to stick by, and pray for wisdom to do this. In Matthew 5:27-30 Jesus reminds us of the seriousness of lust and that it’s better to remove something that’s causing us to sin than to let the sin take over.
• Arm yourself spiritually. Read the Bible on this issue. Talk to pastors or older Christians. Listen to sermons (this one by Josh Harris I found really really helpful). Read books (I really recommend “Sex is not the Problem (Lust is)” by Josh Harris, which also lists some Scripture which is helpful.

Heavenly Father, I pray for my sister. I pray for my sister and my brother. Keep them pure and help them to guard their hearts and their bodies. Help them to honour You with their bodies (1 Corinthians 6:20). I pray that You help them to hate lust. I pray that my sister realises that her boyfriend is the son of the King of Kings, and that she will respect him and show him love, not lust. Help her to see how precious sex is and help her to honour the Giver and the Author of sexuality. Bring this sin into the light so it fades, Lord. I pray You lead them to people who will keep them accountable and pray for them faithfully. I pray that You will speak to them through Your Word. I pray that they will come to You in repentance and trust in the cleansing power of Your blood and in the strength of the Holy Spirit, who enables us to be self-disciplined. Give them patience, Lord, so that they can glorify You. In Jesus’ Name I pray, Amen.