God was very intolerant of syncretism, of Israelites mixing the worship of God with the worship of foreign gods, but what of pagan foreigners themselves? What the Old Testament has to say may surprise you.
Here is just a small sample from the Law:
Do not mistreat an alien or oppress him, for you were aliens in Egypt.
Do not oppress an alien; you yourselves know how it feels to be aliens, because you were aliens in Egypt.
Six days do your work, but on the seventh day do not work, so that your ox and your donkey may rest and the slave born in your household, and the alien as well, may be refreshed.
This is to be a lasting ordinance for you: On the tenth day of the seventh month you must deny yourselves and not do any work—whether native-born or an alien living among you-
Do not go over your vineyard a second time or pick up the grapes that have fallen. Leave them for the poor and the alien. I am the LORD your God.
When an alien lives with you in your land, do not mistreat him.
The alien living with you must be treated as one of your native-born. Love him as yourself, for you were aliens in Egypt. I am the LORD your God.
When you reap the harvest of your land, do not reap to the very edges of your field or gather the gleanings of your harvest. Leave them for the poor and the alien. I am the LORD your God.
You are to have the same law for the alien and the native-born. I am the LORD your God.
If one of your countrymen becomes poor and is unable to support himself among you, help him as you would an alien or a temporary resident, so he can continue to live among you.
The community is to have the same rules for you and for the alien living among you; this is a lasting ordinance for the generations to come. You and the alien shall be the same before the LORD :
The same laws and regulations will apply both to you and to the alien living among you.
And I charged your judges at that time: Hear the disputes between your brothers and judge fairly, whether the case is between brother Israelites or between one of them and an alien.
He defends the cause of the fatherless and the widow, and loves the alien, giving him food and clothing.
Do not abhor an Edomite, for he is your brother. Do not abhor an Egyptian, because you lived as an alien in his country.
Do not take advantage of a hired man who is poor and needy, whether he is a brother Israelite or an alien living in one of your towns.
Do not deprive the alien or the fatherless of justice, or take the cloak of the widow as a pledge.
“Cursed is the man who withholds justice from the alien, the fatherless or the widow.” Then all the people shall say, “Amen!”
So, what about the Prophets? Again, this is just a small sample
The LORD watches over the alien and sustains the fatherless and the widow, but he frustrates the ways of the wicked.
This is what the LORD says: Do what is just and right. Rescue from the hand of his oppressor the one who has been robbed. Do no wrong or violence to the alien, the fatherless or the widow, and do not shed innocent blood in this place.
Do not oppress the widow or the fatherless, the alien or the poor. In your hearts do not think evil of each other.
So, when a Christian mistreats a Pagan, when he or she bears false witness against them or denies them justice, are they obeying the God? Are they obeying God’s laws? Are they listening to God’s prophets?