Questions: I have heard that you believe that when a Christian sins, they are now lost from God and need to be born again, again. Is this true?
Answer: Yes, I would hold when a Christian commits a willful sin then they are not longer saved.
The scriptures that I would use to support this would be, “Whosoever hateth his brother is a murderer: and ye know that no murderer hath eternal life abiding in him” (1Joh 3:15), “If a man say, I love God, and hateth his brother, he is a liar: for he that loveth not his brother whom he hath seen, how can he love God whom he hath not seen?” (1Joh 4:20), and “He that committeth sin is of the devil” (1Joh 3:8).
You can read my article on Sin is Not an Option for the Christian, Committing Sin Brings Spiritual Death, Biblical Definition of Sin, and Sinning and the Greek Present Tense. These will give you a better understanding of what I hold the New Testament teaches concerning what happens when a Christian sins.