Below, please find a brief passage from St. Augustine’s introductory comments on Psalm 98 LXX (99), where he asserts that “our entire attention” (tota intentio nostra) when reading the Old Testament should be directed toward seeing (videre) and understanding (intellegere) Christ there.

Modo ergo tota intentio nostra est, quando Psalmum audimus, quando Prophetam, quando Legem, quae omnia antequam veniret in carne Dominus noster Iesus Christus, conscripta sunt, Christum ibi videre, Christum ibi intellegere. Intendat ergo nobiscum Caritas vestra ad istum psalmum, et quaeramus hic Christum: utique apparebit quaerentibus, qui primo apparuit non quaerentibus; et non deseret desiderantes se, qui redemit neglegentes se.

Now, then, our entire attention when we hear a Psalm, when we hear a prophet, when we hear the law, all of which were written down before our Lord Jesus Christ came in the flesh, is directed toward seeing Christ there, toward understanding Christ there. I ask your charity, then, to join me in directing your attention to this Psalm and in seeking Christ here. He who at first appeared to those who were not seeking him will surely appear to those who are seeking him; and he who redeemed those who were indifferent to him will not desert those who are desiring him.

The translation is my own.