Paul Errs Teaching Salvation by Family Relations
Paul gives a command from God in 1 Corinthians 10:10, but then in 10:12 Paul gives a command from himself: "Unto the married I command, yet not I, but the Lord .., but the rest is from me, not from the Lord” (I Cor. 7:10-12). Paul in saying this did what OT principles required for recognition of a statement as inspired -- he said the message was from "the Lord."
Now what Paul says is "not from the Lord," but himself, begins with verse 12. It is bizarre, spiritually speaking. It is at total odds with Paul's doctrine of salvation by faith. Paul teaches that an unbelieving husband is sanctified by the wife, and likewise the unbelieving wife by the believing husband, and if this were not so also one's children would be "unclean" -- unsaved, but instead are "holy" (saved).
Let's read this in the most literal modern New Testament - the Disciples Literal New Testatment:
But Do Not Divorce Your Christian Spouse
10 But to the ones having married I command (not I, but the Lord), that a wife not be separated from her husband— 11 but if indeed she is separated, let her remain unmarried or let her be reconciled to her husband— and that a husband not leave [a] his wife.
Do Not Divorce an Unbelieving Spouse Who Chooses To Stay
12 But to the rest I say, not [b] the Lord— if any brother has an unbelieving wife and this one consents to dwell with him, let him not leave her. 13 And if any woman has an unbelieving husband and this one consents to dwell with her, let her not leave her husband. 14 For the unbelieving husband has been sanctified[c] by his wife. And the unbelieving wife has been sanctified by the brother. Otherwise then your children are unclean, but now [d] they are holy. (1 Cor. 10:7-14 DLNT.)
Clearly, Paul is off on a theory that contradicts his faith-alone doctrine, and ascribes the cleansing of a sin for one marriage partner to not only automatically apply to their spouse but also to their children. See 1 Cor. 7:10-14. Paul had the good sense not to attribute that idea to God that one's salvation is through close blood-relationships within a single family unit without faith. John the Baptist decried this imparted-salvation idea in Matthew chapter 3 -- the Jews who thought their relationship with "Father" Abraham saved them.