33 To mention only a few things in the times of the kings, at the very outset does not the change in the priesthood when Eli was rejected and Samuel chosen, and in the kingdom when Saul was rejected and David chosen, clearly predict the new priesthood and kingdom to come in our Lord Jesus Christ, when the old, which was a shadow of the new, was rejected? Did not David, when he ate the show-bread, which it was not lawful for any but the priests to eat, prefigure the union of the kingdom and priesthood in one person, Jesus Christ? In the separation of the ten tribes from the temple while two were left, is there not a figure of what the apostle asserts of the whole nation: "A remnant is saved by the election of grace."?
Source: Reply to Faustus the Manichaean (New Advent)