Would it be wrong for me to point out that in the passage from 1st Corinthians
7:10 And unto the married I command, yet not I, but the Lord, Let not the wife depart from her husband: 7:11 But and if she depart, let her remain unmarried, or be reconciled to her husband: and let not the husband put away his wife.
the author is referring to a teaching which is explained in the gospels * Mark
10:2 And the Pharisees came to him, and asked him, Is it lawful for a man to put away his wife? tempting him. 10:3 And he answered and said unto them, What did Moses command you? 10:4 And they said, Moses suffered to write a bill of divorcement, and to put her away. 10:5 And Jesus answered and said unto them, For the hardness of your heart he wrote you this precept. 10:6 But from the beginning of the creation God made them male and female. 10:7 For this cause shall a man leave his father and mother, and cleave to his wife; 10:8 And they twain shall be one flesh: so then they are no more twain, but one flesh. 10:9 What therefore God hath joined together, let not man put asunder.
This covers a case where two believers are married, neither of them is allowed to leave. He doesn't have a saying to agraphify for the next case, so he talks on his own authority * 1st Corinthians
7:12 But to the rest speak I, not the Lord: If any brother hath a wife that believeth not, and she be pleased to dwell with him, let him not put her away. 7:13 And the woman which hath an husband that believeth not, and if he be pleased to dwell with her, let her not leave him. 7:14 For the unbelieving husband is sanctified by the wife, and the unbelieving wife is sanctified by the husband: else were your children unclean; but now are they holy. 7:15 But if the unbelieving depart, let him depart.
And good riddance. Note the veiled cut at these folks, they aren't "really" married. But still, the believer can't leave them.
But he definitely doesnt assert that this application of the teachings is "just his own opinion" in the sense of not being authoritative
7:39 The wife is bound by the law as long as her husband liveth; but if her husband be dead, she is at liberty to be married to whom she will; only in the Lord. 7:40 But she is happier if she so abide, after my judgment: and I think also that I have the Spirit of God.
Paul never has any trouble asserting that his word is THE Word
7:17 But as God hath distributed to every man, as the Lord hath called every one, so let him walk. And so ordain I in all churches.