When trying to determine whether something that is claimed to be a sin actually is a sin, you only need to ask these three questions:
- Does Torah (Genesis-Deuteronomy) have a direct command against it?
- Does Torah list items that are permitted (or required) in a category that the item in question is in but is not on the list?
- Is there a penalty associated with it, but without a direct or indirect command against it?
It really is that simple, as Torah alone defines what is right and wrong. Whatever is contrary to Torah is sin and whatever is not contrary to Torah is not sin. The Prophets do not define sin. Jesus does not define sin. The Apostles do not define sin. Only the Law of Yahweh defines sin. And for those who would say that Yeshua does define sin because he is God, let me remind you that if he is to live a sinless life as a human being, he must abide by the same Law that everyone else is expected to abide by. If he were to teach what is contrary to Torah, then he would have sinned and his death on the cross would be useless for our salvation. Therefore Yeshua does not define sin.
Also, I originally listed just the first two questions, and would have considered things that meet the criteria of the third question as things that God hates but does not forbid. But while writing this post, I changed my mind, hence the third question.
Jesus said to live on every word that comes from the mouth of God (Matthew 4:4). And you're not living on it if you are adding to it or subtracting from it. For the Law says in multiple places, such as Deuteronomy 4:2 and 12:32 to not add to or subtract from God's commandments. This means that once written, the Law of God is read only. Nobody after that can in any way change the Law, not even Jesus after he rose from the dead and ascended into Heaven. The Apostle Paul said multiple times that Torah defines sin, such as Romans 3:20 and 7:7. The Law itself defines sin in multiple places as transgressing the Law.
For any given thing that is claimed to be sinful, answering "yes" to one of the above questions proves the thing in question to be sinful. If the answer to both questions is "no", then the thing in question is not sinful even if it is detrimental or believed to be detrimental.
The first question should be self-explanatory. If God's Law has a direct command against something, then that something in question is a sin. Theft, adultery, lying, murder, and slander are all sinful because the Law has a direct command against each of these. The same for eating animals like pigs [Leviticus 11:7-8]. And if you think of twisting 1 Timothy 4:1 to claim that I'm teaching "doctrines of demons" (as some have done), then you would be calling God a demon, for God himself gave that command.
The second question is a bit more complex than the first. There are some places in God's Law that list of a number of things in a category that are either allowed or required. In these instances, whatever is in that same category that does not make the list is forbidden. A good example of this is the list of holy days in Leviticus 23 that we are to use to honor God. So even if it could be proven that Christmas and Easter did originate within Christianity, it wouldn't change the fact that those days are not on the list of holy days for honoring God, and are therefore sinful to partake in. We may see those days as serving God, but that's not how God sees them.
There are some things that do not have a direct command against them (answer to question 1 is "no") or an indirect command against them (answer to question 2 is also "no"). This is where the third and final question comes in: If God's Law also does not list a penalty for doing something (answer to question 3 is "no"), then the item in question is not a sin. But if there is a penalty listed for doing something, then the item in question is a sin. Otherwise, there would not be a penalty.
A good example of something that has a penalty listed, but no direct or indirect command against it is extramarital sex. In Exodus 22:16-17 and Deuteronomy 22:28-29, if an unmarried couple are caught having sexual relationships, then the man is required to pay the bride price to the woman's father, the two are required to marry (unless the father forbids it), and they are never allowed to divorce. The bride price, can be multiple years worth of wages. And if a woman had this type of sexual relationship, then presented herself as a virgin to another man and her deception was discovered, then the woman could die (Deuteronomy 22:20-21).
In any case where the answer to all three of these questions is "no", then the thing in question is permissible. In fact, since Torah is described as "the Law of Liberty" in James 1:25, then we should approach things in a "freedom by default" manner. That is, unless we can prove it goes against God's Law, we should allow it. Some examples of things that are not against God's Law include dancing, games and sports, and gender-neutral bathrooms, lockers, etc.
There are some things that Yahweh technically allows, but also hates. These things are often identified by whether God's Law has a provision for them, but also a lot of restrictions. One example is divorce, where as I explained in a previous post, is intended to be done only in cases of unfaithfulness in marriage. We also know that Yahweh hates divorce because of Malachi 2:16, where Yahweh explicitly states as much when speaking through one of his prophets.
To summarize: If you cannot prove that something is contrary to God's Law either by (1) a direct command, (2) by not making a list of items allowed or required that are in the same category as the item in question, or (3) by not having any penalty for doing something, then regardless of how sinful you believe it to be or how much you object to it, that thing is not, I repeat, not, a sin.
I'll leave you with this exercise: Exodus 20:26 says, "Nor shall you go up by steps to My altar, that your nakedness may not be exposed on it." So what is the sin here? Is it to build steps up to an altar, to approach the altar naked, or both? Don't forget to prove your answer.