I would like to just say in some previous answers you have said that masturbation is not mentioned as a sin, but it is. We are told in Acts 15:20 to flee from sexual immorality. Today, most of the world sees masturbation as sexual immorality, and it has always been considered that. Because the term isn't used, it doesn't mean that it is not referring to it. That term wasn't around in the first century. That's all I have to say.
You are correct that the word "masturbation" wasn't around in the first century -- English wasn't spoken at that time and "masturbation" is an English term. However, the act of masturbation was known at the time. It isn't a modern-day discovery. And I will agree that for a sin to be condemned, it doesn't have to be specifically mentioned in the Bible. Such is covered in "Is masturbation unacceptable?"
What you are stating is that in passages, such as "Therefore I judge that we should not trouble those from among the Gentiles who are turning to God, but that we write to them to abstain from things polluted by idols, from sexual immorality, from things strangled, and from blood" (Acts 15:20), you see masturbation being included in the term "sexual immorality."
The phrase "sexual immorality" is a weak translation of the Greek word porneia. "Weak" because the phrase is much broader and more vague than the actual Greek word it is supposed to be translating. The English word "fornication" is a more precise translation, but it is being avoided because translators feel it is an archaic term and a hard word. The problem is the vague phrase "sexual immorality" has caused people to lump anything that they feel is sexually wrong into the word, such as pornography and masturbation. As a result you have wives claiming the right to divorce because they caught their husband looking at pornography on the Internet; citing "And I say to you, whoever divorces his wife, except for sexual immorality, and marries another, commits adultery; and whoever marries her who is divorced commits adultery" (Matthew 19:9) as their justification. Matthew 19:9 contains the same Greek word porneia.
The real shame is that people are lumping whatever they assume is in the English phrase "sexual immorality" and then claiming, as you did, that the Greek must also include the same idea. The reasoning is backward, inaccurate, and improper. The word used by the Holy Spirit is porneia. We need to understand what was meant by porneia and then apply that definition.
"Porneia, which is relatively rare in classical Greek (Moulton-Milligan), originally stood for "prostitution" ... In other, later contexts it denotes "unchasity, illicit sexual relations" of any kind ("fornication" is a somewhat archaic but common translation)." [The Complete Biblical Library].Illicit sexual intercourse:
- adultery, fornication, homosexuality, lesbianism, intercourse with animals, etc.
- sexual intercourse with close relatives; Levitcus 18
- sexual intercourse with a divorced man or woman; Mark 10:11
Porneia (fornication) "is used of illicit sexual intercourse…." [W. E. Vine, Expository Dictionary of New Testament Words]
Fornication: "illicit sexual intercourse in general … distinguished from adultery (moicheia) in Matthew 15:19 … used of adultery … in Matthew 5:32; 19:9 [Henry Thayer, Thayer's Greek-English Lexicon, pg. 532].
Fornication: "The New Testament is characterized by an unconditional repudiation of all extra-marital and unnatural intercourse" [Theological Dictionary of the New Testament, Vol. 6, pg. 590].
I know of no reputable Greek lexicon or dictionary that includes pornography or masturbation as a part of the definition of porneia.
One can also go through the Septuagint translation of the Old Testament to see what Hebrew words were translated to porneia to get an idea of what the word meant. You will find:
- zanah - to lie down like a prostitute (Jeremiah 2:20; Micah 1:7)
- zenunim - Harlotry, prostitution (Hosea 1:2; Nahum 3:4)
- zenuth - Unfaithfulness, prostitution (Numbers 14:33; Jeremiah 3:2; Hosea 4:11)
- taznuth - Harlotry, lust (Ezekiel 16:15; 23:7, 11)
The actual Greek word for masturbation was anaphlan, which does not appear in the Bible.
As I pointed out in "Is masturbation sinful or not?" the act of masturbation would fall underneath one category of uncleanness, that of ejaculation. Unclean things in themselves, such as pigs, dead bodies, menstrual periods, etc., were not sinful in and of themselves. Breaking the laws in dealing with unclean things was sinful. Since God did not define the act of masturbation as sinful, nor as righteous, it would be sinful to add or subtract from what God said. Instead, we look at what typically accompanies masturbation and there we find plenty of things to talk about why those accompanying things are wrong. But even here, the accompanying sinful things, such as pornography, are sinful because the Bible condemns pornography (I Thessalonians 4:5), not because someone wants to twist the definition of porneia to include pornography.