D&C 74

The Lord commanded the Prophet Joseph Smith to do a revised translation, or the better use of the word would be an inspired correction, of the scriptures. As he did so, the Lord revealed what Paul meant as he wrote to the Corinthians -

"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." (New Testament 1 Corinthians 7:14)

The Lord explained by revelation -

"...in the days of the apostles the law of circumcision was had among all the Jews who believed not the gospel of Jesus Christ.
3 And it came to pass that there arose a great contention among the people concerning the law of circumcision, for the unbelieving husband was desirous that his children should be circumcised and become subject to the law of Moses, which law was fulfilled.
4 And it came to pass that the children, being brought up in subjection to the law of Moses, gave heed to the traditions of their fathers and believed not the gospel of Christ, wherein they became unholy." (Doctrine and Covenants Section 74:2 - 4)

As I read this, I have come to understand that as a father, one that holds incorrect traditional views, thus being considered an unbeliever, who carries on and teaches such incorrect views to his children, they will most likeling follow such views and become an unbeliever or as Paul wrote, unholy. This was the case with the Jewish law of circumcision. Jews considered children unclean that were not circumcised. Paul taught -

"...little children are holy, being sanctified through the atonement of Jesus Christ..." (Doctrine and Covenants Section 74:7)

The true intent of circumcision was a covenant or a reminder to look forward for redemption through the Messiah. I see two important principles taught here. First that little children are saved through atonement of Jesus Christ and require nothing else, and second, by Paul's own personal recommendation, believers should not be united with unbelievers.

We read in the For the Strength of the Youth pamphlet, the youth are counseled -

"Date only those who have high standards and in whose company you can maintain your standards. A young man and a young woman on a date are responsible to help each other maintain their standards and to protect each other’s honor and virtue. You must honor the sanctity of the priesthood and of womanhood."