Not my words (from CARM) but hopefully it might clear a few things up -
Leviticus says not to eat shellfish (Lev. 11:9-12), use mixed seed or fabrics (Lev. 19:19), harvest the corners of fields (Lev. 19:9), and that homosexuality is wrong (Lev. 18:22; 20:13).
If homosexuality is wrong because Leviticus says so, then shouldn’t we also obey the other laws about shellfish, seed, fabrics, and fields because that is in Leviticus as well?
If not, then why not?
Why would Christians pick and choose what parts of the Bible to follow?
First of all, not all of Leviticus is written to everyone. There were abominations that applied only to the Jews such as eating shellfish, rabbit, and pork, etc., which were things that typologically represented purity before the Lord. We know this because God says, “Speak to the sons of Israel saying…”
He gives instructions to the Israelites, not to the rest of the nations.
So, we can see a host of things that dealt only with Israel.
However, there are abominations that did not apply only to Israel, but to everyone else also. It is in the latter group that homosexuality is listed.
It is a mistake for people to mix topics intended only for Israel with topics that included the non-Israelites.
Furthermore, when we see that the New Testament condemns the idea of homosexuality in Romans 1:26-27, we could see the continuity between Old Testament moral law and New Testament moral law.
A common mistake made by homosexual proponents when discussing the Old Testament, in particular, Leviticus, is the failure to understand the three main divisions of the Law: civil, ceremonial, and moral. This is important because the civil and ceremonial laws are not in effect now, but the moral law is. Homosexuality is under the moral law category. Therefore, we see that the moral aspects of the Law are still in effect, but not the civil or ceremonial.
Again, there were things addressed to Israel only where God said: “speak to the sons of Israel saying…” These things included atonement for unintentional sins, eating habits, uncleanness, feast days, rest days, etc., which do not apply to us today.
Finally, when we see that the New Testament also condemns homosexuality, it is clear that we cannot just dismiss Leviticus as a whole along with its moral regulations on sexual activity.
Homosexuality is clearly condemned in Leviticus and its condemnation cannot be dismissed by saying we are no longer under Old Testament Law.