2 Corinthians 6:15

What harmony can there be between Christ and Belial (Satan)? Or what does a believer have in common with an unbeliever?

1 Samuel 5:2-4

They took the ark of God and brought it into the house of Dagon and set it beside [the image of] Dagon [their chief idol].

1 Kings 18:21

Elijah approached all the people and said, “How long will you hesitate between two opinions? If the Lord is God, follow Him; but if Baal, follow him.” But the people [of Israel] did not answer him [so much as] a word.

Ezra 4:3

But Zerubbabel and Jeshua and the rest of the heads of fathers’ households of Israel said to them, “You have nothing in common with us in building a house to our God; but we ourselves will together build to the Lord God of Israel, just as King Cyrus, the king of Persia, has commanded us.”

Mark 16:16

He who has believed [in Me] and has been baptized will be saved [from the penalty of God’s wrath and judgment]; but he who has not believed will be condemned.

Acts 5:14

More and more believers in the Lord, crowds of men and women, were constantly being added to their number,

Acts 8:20

But Peter said to him, “May your money be destroyed along with you, because you thought you could buy the [free] gift of God with money!

1 Corinthians 10:20-21

On the contrary, the things which the Gentiles (pagans) sacrifice, they sacrifice to demons [in effect], and not to God; and I do not want you to become partners with demons [by eating at feasts in pagan temples].

1 Timothy 5:8

If anyone fails to provide for his own, and especially for those of his own family, he has denied the faith [by disregarding its precepts] and is worse than an unbeliever [who fulfills his obligation in these matters].

1 John 5:11-13

And the testimony is this: God has given us eternal life [we already possess it], and this life is in His Son [resulting in our spiritual completeness, and eternal companionship with Him].

Treasury of Scripture Knowledge

Summary

And what concord hath Christ with Belial? or what part hath he that believeth with an infidel?

Bible References

What concord

1 Samuel 5:2
They took the ark of God and brought it into the house of Dagon and set it beside [the image of] Dagon [their chief idol].
1 Kings 18:21
Elijah approached all the people and said, “How long will you hesitate between two opinions? If the Lord is God, follow Him; but if Baal, follow him.” But the people [of Israel] did not answer him [so much as] a word.
1 Corinthians 10:20
On the contrary, the things which the Gentiles (pagans) sacrifice, they sacrifice to demons [in effect], and not to God; and I do not want you to become partners with demons [by eating at feasts in pagan temples].

Or

Ezra 4:3
But Zerubbabel and Jeshua and the rest of the heads of fathers’ households of Israel said to them, “You have nothing in common with us in building a house to our God; but we ourselves will together build to the Lord God of Israel, just as King Cyrus, the king of Persia, has commanded us.”
Mark 16:16
He who has believed [in Me] and has been baptized will be saved [from the penalty of God’s wrath and judgment]; but he who has not believed will be condemned.
Acts 8:20
But Peter said to him, “May your money be destroyed along with you, because you thought you could buy the [free] gift of God with money!
1 John 5:11
And the testimony is this: God has given us eternal life [we already possess it], and this life is in His Son [resulting in our spiritual completeness, and eternal companionship with Him].

An

1 Timothy 5:8
If anyone fails to provide for his own, and especially for those of his own family, he has denied the faith [by disregarding its precepts] and is worse than an unbeliever [who fulfills his obligation in these matters].

General references

Exodus 20:23
You shall not make other gods [to worship] besides Me; gods of silver or gods of gold, you shall not make [these lifeless idols] for yourselves.
Exodus 34:16
and you might take some of his daughters for your sons, and his daughters would play the prostitute with their gods and cause your sons also to play the prostitute (commit apostasy) with their gods [that is, abandon the true God for man-made idols].
Deuteronomy 7:3
You shall not intermarry with them; you shall not give your daughter to his son, nor shall you take his daughter for your son;
Proverbs 22:24

Do not even associate with a man given to angry outbursts;
Or go [along] with a hot-tempered man,
Amos 3:3

Do two men walk together unless they have made an appointment?