"Wherefore, for this cause the apostle wrote unto the church, giving unto them a commandment, not of the Lord, but of himself, that a believer should not be united to an unbeliever; except the law of Moses should be done away among them,
That their children might remain with circumcision; and that the tradition might be done away, which saith that little children are unholy; for it was had among the Jews;"
Joseph Smith has been commanded to translate the Holy Bible. While doing so he had questions regarding 1 Corinthians 7:14 and received this revelation as an explanation. This scripture had often been used to justify infant baptism, an incorrect principle. There are only 7 verses and each is very important to understand Paul's counsel to the Church.
"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." (1 Corinthians 7:14)
The council is that unbelievers not marry, unless the law of Moses is done away between them. That is how the believing husband or wife sanctifies the other. The practice of circumcision was to be done away. Such a practice said the child was unholy otherwise. The chapter ends in verse 7 "But little children are holy, being sanctified through the atonement of Jesus Christ; and this what that scriptures means."
I sat and pondered on how a mystery of God was now made known through personal revelation. How glorious that is.