I heard Christian symbols have pagan origins. Is is wrong to wear a cross or other symbol?
In the Law given to Israel, the Lord commanded in Exodus 20:4-6:
You shall not make for yourself an idol, or any likeness of what is in heaven above or on the earth beneath or in the water under the earth. You shall not worship them or serve them; for I, the LORD your God, am a jealous God, visiting the iniquity of the fathers on the children, on the third and the fourth generations of those who hate Me, but showing lovingkindness to thousands, to those who love Me and keep My commandments.
This commandment prohibited the sin of idolatry, worshipping graven images. A graven image is a likeness of God, and anything we might imagine to represent God will be - by necessity - incomplete and insufficient. The Creator of Heavens and Earth cannot be compared with His Creation. Furthermore, the context of the commandment is that we are not to make such an object for the express purpose of worship.
We know that the making of an image of Heaven by itself is not sinful, since God Himself commanded Moses to make cherubim (angels) that were on the top of the Ark of the Covenant. He also commanded Moses to make a bronze serpent that the Israelites were to look at so they’d be healed if they were bitten by the poisonous snakes God sent to punish them (Numbers 21). God's concern was making an image for the purpose of worshipping it (as the Israelites did in the desert in Exodus 32).
In fact, Hezekiah ended up destroying the bronze serpent because eventually the Israelites did begin to worship it (1 Kings 18). So, we see that making an image of something is not in and of itself against God’s commandment. Importantly, as a side note, Christians are not under the Mosaic Law; however, this same law overlaps commandments we receive in the New Testament that expressly forbid idolatry (e.g., 1 Corinthians 10:14).
Furthermore, we read in Genesis 24 that Rebekah is given a ring and bracelets when she is chosen to be Isaac’s wife. 1Peter 3:3-4 says,
“Your adornment must not be merely external--braiding the hair, and wearing gold jewelry, or putting on dresses; but let it be the hidden person of the heart, with the imperishable quality of a gentle and quiet spirit, which is precious in the sight of God.”
Adornment here is not prohibited, but it is to be modest so that a woman’s spiritual adornment from God can be seen. A similar command is given in 1 Timothy 2:9-10.
Therefore, we see that God’s word allows for us to wear jewelry, which would include a cross, chi-rho, fish, or Trinity sign, whether worn on our person or on our car. Having said that, there are things to consider before wearing such jewelry or putting them on our cars.
First, if we fellowship regularly with a Christian brother or sister who (incorrectly) believes that wearing such jewelry is sinful, then we should not wear the jewelry for the sake of our weaker (in the faith) brother or sister. This is clearly stated as a commandment in Romans 14.
Second, and this is my opinion (based on God’s word) rather than God’s explicit word, we should be careful about putting such symbols on our car or wearing such jewelry. People understand what the fish symbol means, and what the cross means. If our witness is such that we do things that are not Christ-like, people are much more apt to have a negative view of Christianity, and God is not glorified.
For example, my pastor, who is an ex-policeman, tells the story of the lady he pulled over for speeding. He had been trying to witness to his partner about Christ. When they proceeded to give the lady a speeding ticket, she began spewing profanity because she was angry that she got caught speeding. Yet, she had a Christian fish symbol on her car, which my pastor’s partner noticed. In this way, the lady set a poor example of what a Christian looks like.
The point here is that when we “advertise” that we are a Christian, we better be the real deal, or else the world thinks we are fake, just like everyone else. Better to let our good works shine before men so that our Father in heaven is glorified. Indeed, that is the point in both the 1 Peter and 1 Timothy passages cited above.
In summary, it is not sinful to wear a cross or put Christian symbols on our cars, as long as we do not worship them, making them an idol. Also, we are to take into consideration how other Christians with whom we regularly fellowship view this, so as not to sear their conscience. Finally, we need to be imitators of Christ, walking as He walked. Wearing these symbols makes that all the more important.