I write to you because I want to read your answer more carefully and I believe that a written response will be more crafted. I've already read the material you have on the website about masturbation while one still a single person and the subject was closed to me for.
Recently, however, I saw an argument that I did not think about before. As far as I understand, the pastor said, using I Corinthians 7:9, that Paul is saying marriage is the only legitimate way to satisfy all sexual desires. Thus, masturbation is a sin. The expression "burning with passion" encompasses all unsatisfied sexual desires. The word porneia, which was also a topic of attention on your website and many other studies, could also include masturbation. I find the last point unlikely since Jesus affirms in Matthew 19:9 that immorality (porneia) is the only lawful motive for divorce. This would mean by extension that a spouse could divorce another if one masturbated.
Following the principle established in Romans 14:23, I'm trying to not engage in this activity while I think this through. I'm also trying not to just justify myself in an "accommodation" that I already have.
What are your thoughts?
"Now concerning the things about which you wrote, it is good for a man not to touch a woman. But because of immoralities, each man is to have his own wife, and each woman is to have her own husband. The husband must fulfill his duty to his wife, and likewise also the wife to her husband. The wife does not have authority over her own body, but the husband does; and likewise also the husband does not have authority over his own body, but the wife does. Stop depriving one another, except by agreement for a time, so that you may devote yourselves to prayer, and come together again so that Satan will not tempt you because of your lack of self-control. But this I say by way of concession, not of command. Yet I wish that all men were even as I myself am. However, each man has his own gift from God, one in this manner, and another in that. But I say to the unmarried and to widows that it is good for them if they remain even as I. But if they do not have self-control, let them marry; for it is better to marry than to burn with passion" (I Corinthians 7:1-9).
In looking at the context of what Paul was stating, is he discussing single people or couples? I would argue that he is discussing the relationship between a man and a woman.
He does suggest singleness in I Corinthians 7:6-7, but not as a command. Whether a person chooses to marry or not is a personal choice. God is not commanding one choice over another. Paul chose the single life (I Corinthians 9:5) and wishes that everyone could make that same choice when needed. A bit later Paul states that his reason for the suggestion is his knowledge that severe persecution was on the horizon (I Corinthians 7:26). Paul sees being single as a less demanding and less complicating choice, but he knows it isn't for everyone. In I Corinthians 7:8, he suggests that those not yet married or no longer married remain single for the time. He states that it is a good choice but not necessarily a better choice.
However, Paul states that singleness isn't for everyone. Different people have different preferences which will lead them to make different choices. Some are well suited for the married life while others are better suited for the single life. However, if a single life would lead a person to commit fornication because they are weak in this area of self-control, then they ought to marry. Any possible advantage to remaining single is greatly outweighed by sin.
In the Greek, the last phrase is "for it is better to marry than to burn." Translators have added "with passion" to make it clearer what kind of burning Paul was discussing. The Greek word puroo means to set on fire or burn. Figuratively it means to fan the flames of emotions, especially sexual desire. Again, the context is that the lack of self-control would lead a man and woman to commit a sexual sin fueled by their desire for sex.
Thus, all we have is one man's claim that fornication (porneia) and burning (puroo) includes masturbation. Yet, the context is discussing couples. Masturbation is an act done alone unless you want to talk about mutual masturbation, which actually a part of sex between two people. Every Greek dictionary and source that I know of defines porneia as acts of sex between two people (see: Sex). See also: Is masturbating a lack of self-control?
This preacher would need to prove his point with documentation beyond his simple assertion.