The words of the apostle:  “Ever learning, and never able to come to the knowledge of the truth” (2 Tim. 3:7), apply to many learned commentaries.  Their authors have brought to them much accurate scholarship and research; but they have not seen the unity of divine truth.  They have written mainly in an antiquarian spirit and interest, regarding the work under consideration simply as an ancient and venerable record.  They have diligently sought for connections in philology, in antiquities, and in history.  In these respects they have thrown much light on the sacred text.  But they have never once thought of inquiring what place the book which they have undertaken to interpret holds in the divine system of revelation—­perhaps have had no faith in such a system.  Consequently they cannot unfold to others that which they do not themselves apprehend.  On a hundred particulars they may give valuable information, but that which constitutes the very life and substance of the book remains hidden from their view.

2.  It is necessary that we understand, first of all, the relation of the Old Testament as a whole to the system of revealed truth.  It is a preparatory revelation introductory to one that is final.  This the New Testament teaches in explicit terms.  “When the fulness of the time was come, God sent forth his Son.”  Gal. 4:4.  Christ could not have come in the days of Enoch before the flood, nor of Abraham after the flood, because “the fulness of the time” had not yet arrived.  Nor was the way for his advent prepared in the age of Moses, or David, or Isaiah, or Ezra.  The gospel everywhere assumes that when the Saviour appeared, men had attained to a state of comparative maturity in respect to both the knowledge of God and the progress of human society.  The attentive reader of the New Testament cannot fail to notice how fully its writers avail themselves of all the revelations which God had made in the Old Testament of himself, of the course of his providence, and of his purposes towards the human family.  The unity of God, especially, is assumed as a truth so firmly established in the national faith of the Jews, that the doctrine of our Lord’s deity, and that of the Holy Spirit, can be taught without the danger of its being misunderstood in a polytheistic sense—­as if the Father, the Son, and the Holy Spirit were three gods.  It is certain that this could not have been done any time before the Babylonish captivity.  The idea of vicarious sacrifice, moreover—­that great fundamental idea of the gospel that “without shedding of blood there is no remission”—­the writers of the New Testament found ready at hand, and in its light they interpreted the mission of Christ.  Upon his very first appearance, John the Baptist, his forerunner, exclaimed to the assembled multitudes:  “Behold the Lamb of God, which taketh away the sin of the world.”  To the Jew, with his training under the Mosaic system of sacrifices, how