The answer seems to be—from Abraham.
God taught Moses more, much more than he taught Abraham. It was Moses who bade men call God Jehovah, the I AM; but who, hundreds of years before, taught them to call him the Almighty God?
The answer seems to be, Abraham. God, we read, appeared to Abraham, and said to him, ‘Get thee out of thy country, and from thy father’s house, unto a land that I shall show thee, and I will make of thee a great nation.’ And again the Lord said to him, ‘I am the Almighty God, walk before me and be thou perfect, and thou shalt be a father of many nations.’
‘And Abraham believed God, and it was counted to him for righteousness. And he was called the friend of God.’
But from what did Abraham turn to worship the living God? From idols? We are not certain. There is little or no mention of idols in Abraham’s time. He worshipped, more probably, the host of heaven, the sun and moon and stars. So say the old traditions of the Arabs, who are descended from Abraham through Ishmael, and so it is most likely to have been. That was the temptation in the East. You read again and again how his children, the Jews, turned back from God to worship the host of heaven; and that false worship seems to have crept in at some very early time. The sun, you must remember, and the moon are far more brilliant and powerful in the East than here; their power of doing harm or good to human beings and to the crops of the land is far greater; while the stars shine in the East with a brightness of which we here have no notion. We do not know, in this cloudy climate, what St. Paul calls the glory of the stars; nor see how much one star differs from another star in glory; and therefore here in the North we have never been tempted to worship them as the Easterns were. The sun, the moon, the stars, were the old gods of the East, the Elohim, the high and mighty ones, who ruled over men, over their good and bad fortunes, over the weather, the cattle, the crops, sending burning drought, pestilence, sun-strokes, and those moon-strokes which we never have here; but of which the Psalmist speaks when he says, ‘The sun shall not smite thee by day, neither the moon by night.’ And them the old Easterns worshipped in some wild confused way.
But to Abraham it was revealed that the sun, the moon, and the stars were not Elohim—the high and mighty Ones. That there was but one Elohim, one high and mighty One, the Almighty maker of them all. He did not learn that, perhaps, at once. Indeed the Bible tells us how God taught him step by step, as he teaches all men, and revealed himself to him again and again, till he had taught Abraham all that he was to know. But he did teach him this; as a beautiful old story of the Arabs sets forth. They say how (whether before or after God called him, we cannot tell) Abraham at night saw a star: and he said, ‘This is my Lord.’ But when the star set, he said, ‘I like not those who vanish away.’ And when he saw the moon rising, he said, ‘This is my Lord.’ But when the moon too set, he said, ‘Verily, if my Lord direct me not in the right way, I shall be as one who goeth astray.’ But when he saw the sun rising, he said, ‘This is my Lord: this is greater than star or moon.’ But the sun went down likewise. Then said Abraham, ‘O my people, I am clear of these things. I turn my face to him who hath made the heaven and the earth.’
And was this all that Abraham believed—that the sun and moon and stars were not gods, but that there was a God besides, who had made them all? My friends, there have been thousands and tens of thousands since, I fear, who have believed as much as that, and yet who cannot call Abraham their spiritual father, who are not justified by faith with faithful Abraham.
For merely to believe that, is a dead faith, which will never be counted for righteousness, because it will never make man a righteous man doing righteous and good deeds as Abraham did.
Of Abraham it is written, that what he knew, he did. That his faith wrought with his works. And by his works his faith was made perfect. That when he gained faith in God, he went and acted on his faith. When God called him he went out, not knowing whither he went.
His faith is only shown by his works. Because he believed in God he went and did things which he would not have done if he had not believed in God. Of him it is written, that he obeyed the voice of the Lord, and kept his charge, his commandments, his statutes, and his laws.