Another beautiful incident in connection with the childhood of Isaac is, that Sarah, his mother, even at her advanced age and exalted station in life, did not deem it a burden to nurse him. Calvin has well said, “Whom God counts worthy of the honor of being a mother He at the same time makes a nurse; and those who feel themselves burdened through the nursing of their children, rend, as far as in them lies, the sacred bond of nature, unless weakness, or some infirmities, form their excuse.” But along with the growing child is the mocking Ishmael. He was fourteen years of age at the birth of Isaac, and therefore in the first years of Isaac, appears as a playful lad, and true to his nature, doubtless developed a characteristic trait of jealousy which would not escape the ever watchful eye of Sarah, as she observed his dancing and leaping, and now and then making hateful faces at the mother’s darling, mocking his childish fears and appeals to the mother for protection. This seems to have been endured by Sarah until the great feast day, held to celebrate the weaning of Isaac. Seeing special attention paid to Isaac by all the invited guests, his jealousy suddenly developed into envy, and this, in turn, found expression in mockery. Sarah could endure these mockings no longer, for to her sensitive nature, Ishmael’s mocking the child of promise was but the outward expression of his unbelief in the faith of his parents, and therefore the word and purpose of God. His conduct revealed his unbelief, and hence was unworthy and incapable of sharing in the blessing, which then, as now, was secured only by faith, and which had already cost her so much. Hence she said to Abraham, “Cast out this bondwoman and her son.” The treatment may seem harsh, but there could be no peace or happiness in that household until the mocking Ishmael was out of it. This mother, whose spiritual faith had been quickened in a marvelous manner, was clear-sighted enough to see that the purposes of God in reference to Isaac could only become actual through this separation. The fact that the prompt, sharp determination that “the son of this bondwoman shall not be heir” with Isaac, “was very grievous in Abraham’s sight,” shows that his prejudice in favor of the rights of the natural first-born needed correction. And God confirmed the judgment of Sarah. For the exclusion of Ishmael was requisite not only to the prosperity of Isaac and the line of the promise, but to the welfare of Ishmael himself. And the man of faith, who should later offer up Isaac, must now be able to offer up Ishmael also. After the sending away of Hagar and her son Ishmael, there is but one incident recorded in the life of Abraham, namely the treaty or covenant of peace with Abimelech, King of Gerar, though probably several years passed away between the departure of Hagar and the last great test or trial of Abraham in the offering up of Isaac on Mt. Moriah.