Once a person trusts Christ they become a member of the family of God. This family knows no barriers whether they might be racial, geographical, economical, or social. We are all one in Christ. Male or female, rich or poor, free or slave we are all in God's family.

Seek the Godly

Their best friends and closest acquaintances should be believers.

And let us consider how to provoke one another to love and good deeds, not neglecting to meet together, as is the habit of some, but encouraging one another, and all the more as you see the Day approaching (Hbr 10:24-25).

Separate from Unbelievers

The Bible also says that we should separate ourselves from unbelievers.

Therefore come out from them and be separate, says the Lord. Touch no unclean thing, and I will receive you (2Cr 6:17).

Have Some Contact

However this does not mean that Christians should entirely give up their non-believing friends. There has to be contact with those who do not know Christ.

As his custom was, Paul went into the synagogue, and on three Sabbath days he reasoned with them from the Scriptures, explaining and proving that the Christ had to suffer and rise from the dead. "This Jesus I am proclaiming to you is the Christ," he said (Act 17:2-3).

We find that the Apostle Paul was accustomed to going to the synagogue ever week to share his faith with the unbelievers.

Summary

The believer should seek fellow-believers as their closest friends since we are all members of God's family. We are to separate ourselves from unbelievers. However we are not to totally cut ourselves off from the unbelievers. They should be the object of our evangelism as we make known to them the good news about the Lord Jesus.