Christ is the central sun of the whole book

And he said to them, “O foolish ones, and slow of heart to believe all that the prophets have spoken! Was it not necessary that the Christ should suffer these things and enter into his glory?” And beginning with Moses and all the Prophets, he interpreted to them in all the Scriptures the things concerning himself. —Luke 24:25-27 

J.C. Ryle explains:

How shall we explain these words? In what way did our Lord show “things concerning himself,” in every part of the Old Testament field? The answer to these questions is short and simple. Christ was the substance of every Old Testament sacrifice, ordained in the law of Moses. Christ was the true Deliverer and King, of whom all the judges and deliverers in Jewish history were types. Christ was the coming Prophet greater than Moses, whose glorious advent filled the pages of prophets. Christ was the true seed of the woman who was to bruise the serpent’s head–the true seed in whom all nations were to be blessed–the true Shiloh to whom the people were to be gathered, the true scape-goat–the true bronze serpent–the true Lamb to which every daily offering pointed–the true High Priest of whom every descendant of Aaron was a figure. These things, or something like them, we need not doubt, were some of the things which our Lord expounded in the way to Emmaus.

Let it be a settled principle in our minds, in reading the Bible, that Christ is the central sun of the whole book. So long as we keep Him in view, we shall never greatly err in our search for spiritual knowledge. Once losing sight of Christ, we shall find the whole Bible dark and full of difficulty. The key of Bible knowledge is Jesus Christ.