the advantage

Joseph Fielding Smith: President Brigham Young has said, "When a man and woman have received their endowments and sealings, and then had children born to them afterwards, these children are legal heirs to the kingdom and to all its blessings and promises, and they are the only ones that are on this earth." This is certainly true; how can children whose parents have not been married by divine authority be heirs of that kingdom?

It may be asked, what is the advantage coming to those born under the covenant? Being heirs they have claims upon the blessings of the gospel beyond what those not so born are entitled to receive. They may receive a greater guidance, a greater protection, a greater inspiration from the Spirit of the Lord; and then there is no power that can take them away from their parents. Children, on the other hand, who are born to parents who were married until death separates them, have no claim upon such parents, and such parents have no claim upon the children after the resurrection from the dead.

(Book: "Doctrines of Salvation," 1954-1956, vol. 2, p. 90)