In the 9th chapter of Ezra, the priestly leader is made aware of a great problem 
among the remnant of Jews who had returned to help rebuild the city of Jerusalem and re-inhabit the land of Judah. Many of them – contrary to God’s commands – had married spouses from surrounding pagan nations. To us in the 21st century that prohibitive command sounds very narrow and judgmental but God was protecting his people and more importantly his plan of salvation. The Israelites were in a unique covenant with God; they were to be the nation that followed the one, true God only and in so doing would set the stage for the coming of the Savior. But God knew that if his people, the Jews, intermarried with unbelievers that it would weaken their faith and ultimately their divine purpose. Biblical history records that such pagan intermarriage nearly destroyed King Solomon and other good leaders. Prior to their Babylonian captivity, this one sin is what introduced idolatry into the land of Israel and nearly destroyed God’s plan.
This incident in the book of Ezra should be a reminder that relationships impact our faith more than anything else in this world. Paul writes in 1 Corinthians, 33 Do not be misled: “Bad company corrupts good character.” (1 Cor 15:33) In his second letter to the same church Paul writes this, 14 Do not be yoked together with unbelievers. For what do righteousness and wickedness have in common? Or what fellowship can light have with darkness? (2 Cor 6:14) Here’s the point: while we need to build relationships with non-believers in the hopes that we can introduce them to Jesus, we should be careful in building partnerships with unbelievers. In a partnership (business, marriage, etc.) there is the danger is that even a strong believer can be negatively influenced by a non-believer. So don’t compromise or let down your guard. Your faith in Jesus Christ is more important than anything else in this world – preserve it at all costs!