What does the Bible say about an unsaved person being divorced and now has remarried but since has given their life to God (before they remarried)?
"But I say unto you, That whosoever shall put away his wife, saving for the cause of fornication, causeth her to commit adultery: and whosoever shall marry her that is divorced committeth adultery." (Matthew 5:32)
"And I say unto you, Whosoever shall put away his wife, except it be for fornication, and shall marry another, committeth adultery: and whoso marrieth her which is put away doth commit adultery." (Matthew 19:9)
"And he saith unto them, Whosoever shall put away his wife, and marry another, committeth adultery against her. And if a woman shall put away her husband, and be married to another, she committeth adultery." (Mark 10:11-12)
"Whosoever putteth away his wife, and marrieth another, committeth adultery: and whosoever marrieth her that is put away from her husband committeth adultery." (Luke 16:18)
"And unto the married I command, yet not I, but the Lord, Let not the wife depart from her husband: But and if she depart, let her remain unmarried, or be reconciled to her husband: and let not the husband put away his wife." (1 Corinthians 7:10)
If you are Jewish, "When a man hath taken a wife, and married her, and it come to pass that she find no favour in his eyes, because he hath found some uncleanness in her: then let him write her a bill of divorcement, and give it in her hand, and send her out of his house. 2And when she is departed out of his house, she may go and be another man's wife." (Deuteronomy 24:1-2)
That is what the Bible says. Men's interpretations vary. Some are as follows:
Again, those are all interpretations of men. Study the scriptures given above and see what they say, and what they don't say. Another thing to consider is God's grace and mercy. The safest interpretation is the first, that the divorced person should not remarry. That is the safest, but I am not going to be dogmatic that it is the right one.