He was obliged to go forth by faith. The removal meant the severing of every earthly tie. Wealth and ease were exchanged for a wandering life. How he could make a living Abraham did not know. How he could educate his children he did not understand. But he went forth Terah, his father, and Lot, his nephew, went with him. They halted at Haran, a smaller city, and remained there until the father’s death. Then came the command to go forward. Out into a new country he went, a pilgrim and a stranger. “By faith Abraham, when he was called to go out into a place which he should after receive for an inheritance, obeyed; _and he went out, not_ knowing whither he went. By faith he sojourned in the land of promise, as in a strange country, dwelling in tabernacles with Isaac and Jacob, the heirs with him of the same promise; for he looked for a city which hath foundations, whose builder and maker is God.” “He staggered not at the promise of God through unbelief; but was strong in faith.”[15] [Sidenote: Called to teach] It was when the patriarch had journeyed into this strange land, and knew not whither he was going, that his work as a teacher began. The commission of Christ to the apostles, “Go ye therefore, and _teach_ all nations,” was not more emphatic than the command to Abraham. God called him to teach, and he was to be a teacher of nations. To the disciples it was said, “All power is given unto Me; ... go ye therefore, and teach all nations.” A power was to attend their teaching. Power is synonymous with life; there is no power without life, and a teacher has power in proportion as he _lives_ what he wishes to teach. Abraham was to be a teacher of nations, hence he must have power. Power could come only as the result of a life of faith, and so his whole life was one continual lesson of faith. Each experience made him a more powerful teacher. [Sidenote: God prepares Abraham to teach] His faith grew by trial, and only as he mounted round by round the ladder which spanned the gulf twixt heaven and earth, and which had seemed to lengthen with each succeeding generation. A period of not less than twenty-five years—years filled with doubt, fear, anxiety—was necessary to bring him to the place where the name _Abraham_—the father of nations—could be rightly claimed by him. Another quarter of a century rolled over his head, years in which he watched the growth of the child of promise; then the voice of God called him to raise his hand to take the life of that same son. He who had said that in Isaac should all nations of the earth be blessed, now demanded the sacrifice of that life at the father’s hand. But He, the Life-giver in the event of the child’s birth, was now believed to be the Life-giver should death rob him of his child, and the father faltered not.