Going and joining are two different things John. Read Hebrews 7:26 and II Corinthians 6:14-18 It is not everyone that does God's work that goes, Matthew 7:21-25

But how do you minister to those you do not know? makes it kinda hard. I have a christian brother who is a great help to me and he is a greek. So no matter what bible verses you give me to tell him he should not be it is ultimately a matter of personal choice.

I see your point--however,other things are just a matter of choice as well--like committing adulterly, fornication, taking illegal drugs, using profanity, etc. God's Word is here for us (for those who choose Christ as Lord and Savior) as a guide.

2Timothy 3:16 says "All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness"

So --when scriptures are given to respond to those who choose to take a greek oath, God's Word speaks to the truth about what this entails. To ignore God's Word is to ignore God. This is to carry a rebellious attitude that says "I can do waht I want becuase I don't see the hamr in it." This is dangerous!

So what kind of other personal choices can your friend make?
Category 1- Can he smoke cigarettes? Can he smoke marajuana? Can he smoke crack?
Category 2- Can your friend watch Rocky? Can your friend watch Fatal Instinct (The one with Mike Douglass)? Can your friend watch pornography?
Category 3- Can your friend look at a woman? Can you friend like what he sees? Can he lust at what he sees?

These are a matter of personal choice. But what can he do and not do. Be careful! Each category is different and slightly complex. Remember! No I can't give you that hint. I need to see where you are coming from.

Question: Are you saved? Yes or no! Do you believe in the absoluteness(not sure if this is a word.) of John 14:6?