“Christian, acknowledge thy dignity, and becoming a partner in the Divine nature, refuse…”

Christian, acknowledge thy dignity, and becoming a partner in the Divine nature, refuse to return to the old baseness by degenerate conduct.

Leo I · The Letters and Sermons · NPNF2 XII, Sermon XXI

Agnosce, o Christiane, dignitatem tuam. The most reproduced sentence Leo wrote outside the Tome, read in the Roman office at Christmas and still quoted in the Catechism. The argument of the whole Nativity sermon turned on the hearer in one clause: what was assumed is what you now are, so behave accordingly.