1 John 3: 4-10: 4 Everyone who makes a practice of sinning also practices lawlessness; sin is lawlessness. 5 You know that he appeared in order to take away sins, and in him there is no sin. 6 No one who abides in him keeps on sinning; no one who keeps on sinning has either seen him or known him. 7 Little children, let no one deceive you. Whoever practices righteousness is righteous, as he is righteous. 8 Whoever makes a practice of sinning is of the devil, for the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the works of the devil. 9 No one born of God makes a practice of sinning, for God’s[b] seed abides in him, and he cannot keep on sinning because he has been born of God. 10 By this it is evident who are the children of God, and who are the children of the devil: whoever does not practice righteousness is not of God, nor is the one who does not love his brother.
I think that John is pretty clear in part of his letter. One cannot be in sin and still claim to be in the light. One cannot be active in a sinful lifestyle and still say that they are practicing righteousness. One cannot claim that they are on a journey to find their place in the church while still harboring unrepentant sin. We cannot be living and acting out in an unrepentant sinful manner and be in the light of Jesus Christ. It is not possible. As John says in his gospel, Jesus is light, and in Him there is no darkness. If we are making a practice of sinning then we are of the devil, and the devil has deceived us into believing that we are not sinning, that because we are devoted to each other in love that God does not care that we are not married or that we are of the same sex.
Wrong! Wrong! Wrong! We cannot be any more wrong. There is no relationship that is acceptable to Christ and the Father except two: a celibate or life of abstinence before marriage or a man and a woman (singular) who are married. In no other context is sex allowed by God. It was in the context of marriage that He blessed Adam and Eve and told them to be fruitful and multiply. Trust me, my flesh wishes it were true otherwise. My flesh wants to have sex with multiple partners. My flesh wants me to have an affair or sexual fling or something. Why? Because it is an act contrary to the will of God. My flesh wants to sin with abandon but the Spirit of Christ living within keeps me true to the will of God.
Were there times when I ignored the Spirit and indulged the flesh? Of course there was. Ask anyone who has been around and I guarantee that there would be a unanimous vote to the affirmative that they have ignored the voice of the Spirit at some point in their Christian life. In the story of the adulterous woman, the older men dropped their stones first because they knew they were not without sin. Paul warns against those who practice indulgences of the flesh because they will not inherit the Kingdom.
I need to practice righteousness. Why? Because if I am practicing righteousness then I am not practicing sinning. But why is loving my neighbor relevant to practicing righteousness? For one, we commanded to love our neighbor more than we love our selves, and second, if we are loving our neighbor as Jesus loved us then we find it impossible to lust after someone who is a brother or sister in Christ.