Here’s a wonderful article from Peter Saunders.
An argument frequently advanced by those attempting to defend homosexual practice is that Christians ‘cherry pick’ the commands in the Bible – that is, they chose to emphasise some commands while ignoring others.
The Old Testament may forbid homosexual acts (Leviticus 18:2; 20:13) but it also forbids eating seafood without fins and scales (Leviticus 11:9-12; Deuteronomy 14:9, 10).
So how can Christians then justify upholding laws on sexual morality whilst at the same time ignoring the food laws from the very same books of the Bible? Why may they eat shellfish but not be allowed to have sex outside marriage? Isn’t this inconsistent and hypocritical?
The solution is that God enters into “covenants” with his people, and the terms of those covenants change.
Especially dietary laws:
The answer to this question lies in an understanding of biblical covenants.
A covenant is a binding solemn agreement made between two parties. It generally leaves each with obligations. But it holds only between the parties involved.
There are a number of biblical covenants: Noahic, Abrahamic, Sinaitic (Old), Davidic and New.
Under the Noahic covenant, which God made with all living human beings (Genesis 9:8-17), people were able to eat anything:
‘Everything that lives and moves about will be food for you. Just as I gave you the green plants, I now give you everything’ (Genesis 9:3).
But under the Sinaitic (Old) Covenant, which God made with the nation of Israel, people were able to eat certain foods, but not others.
Jesus clearly created a new covenant with his followers, where the dietary laws are lifted:
Jesus said that he had come to fulfil the ‘Law and the Prophets’ (Matthew 5:17; Luke 24:44). He would establish this new covenant with new laws, with himself as high priest based on his own sacrificial death on the cross.
This new covenant would completely deal with sin (Hebrews 10:1-18) and protect all those who put their faith in him from God’s wrath and judgement…
[…]‘In the same way, after the supper (Jesus) took the cup, saying, “This cup is the new covenant in my blood, which is poured out for you”’ (Luke 22:20). ‘…we have been made holy through the sacrifice of the body of Jesus Christ once for all’ (Hebrews 10:10)
People would come under the protection of this new covenant, not by virtue of belonging to the nation of Israel, but through faith in Christ. In fact the function of the Old Testament Law (Sinaitic covenant) was to point to Christ as its fulfilment.
[…]So what then did Christ say about foods? He pronounced all foods clean for his followers to eat:
‘ “Don’t you see that nothing that enters a person from the outside can defile them? For it doesn’t go into their heart but into their stomach, and then out of the body.” (In saying this, Jesus declared all foods clean.) He went on: “What comes out of a person is what defiles them. For it is from within, out of a person’s heart, that evil thoughts come—sexual immorality, theft, murder, adultery, greed, malice, deceit, lewdness, envy, slander, arrogance and folly. All these evils come from inside and defile a person.” (Mark 7:18-23)
Jesus was making that point that under the new covenant God required purity of the heart. Internal thoughts and attitudes were as important as external actions.
So, for Christians, the dietary / ceremonial laws don’t apply, but the moral laws do apply. Food is OK for Christians, but sexual immorality – which includes premarital sex and adultery – are NOT OK for Christians.
I think sometimes when you are talking to people whose motivation is just to get rid of any objective moral law entirely, they tend to ask questions without really wanting a good answer. This is especially true when it comes to the morality of sex. They ask the question not to get an answer, but to justify getting rid of the moral rules governing sexuality. The answers are there for people who are willing to respect God in their decision-making. The answers are not found only by people who have a reason to not want to find them.