Sarah's age and Abraham's infirmities rendered the birth of Isaac a natural impossibility, but God had promised the child to Abraham, so the fulfillment of the promise made it necessary that every hindrance should be removed, and that the child should be born.  "Now we, brethren, as Isaac was, are the children of promise," (Gal. 4:28) and the new birth is with men impossible---no human being can confer this upon anyone, or aid in doing it, yet with God all things are possible.  He can "of these stones raise up children to Abraham."  We are "the children of promise."

Every new birth is but the fulfillment of a promise, and "He hath blest us with all spiritual blessings---according as He hath chosen us in Him before the foundation of the world."  So "all Israel shall be saved," and this "all Israel" includes every promised or chosen child---every one who is born, "not of blood, nor of the will of the flesh, nor of the will of man, but of God."  The will had some place in the birth of Ishmael, but not in the birth of Isaac.

A great revivalist can determine time, place, and many of the circumstances of conversions effected by him, but these shall not be heir with the children of the free woman, but shall be cast out.  Ishmael mocked at Isaac.  Perhaps at that time he did not know that he was not the heir.  He did not know that the one he mocked was the heir.  We read of some who were ignorant of God's righteousness and went about to establish their own righteousness.  It is a mercy to be a child of promise.  "The children of the promise are counted for the seed."  "We love him because he first loved us."    ---Elder J. H. Oliphant    Zion's Advocate, 1912