Can a Christian be together with a non-christian? What does the Bible say?
The word of God directs that believers (Christians) must be cautious in selecting partnerships - both business relationships and marriage relationships. Specifically, the Apostles Paul taught that the Lord wanted believers to be in union with other believers, since believers and unbelievers lack a common understanding of the spiritual truths that should guide our thinking and decision-making.
In 1 Corinthians, Paul wrote:
On the other hand, the Bible does NOT teach that Christians should not associate with non-Christians. On the contrary, we are told to go out into the world (of unbelievers) and become ambassadors for Christ. Jesus Himself said that He did not want His disciples to leave the world, because we are here to spread the message of the Gospel to unbelievers (see John 17).