Late Middle English; earliest use found in John Wyclif (d. 1384), theologian, philosopher, and religious reformer. From post-classical Latin ora pro nobis, lit. ‘pray for us’ (Vulgate, e.g. Jeremiah 42:2, 42:20), a plea for intercession; used as a response in various litanies, as the Litany of the Blessed Virgin, the Litany of the Saints, etc. from classical Latin ōra, 2nd person imperative singular of ōrāre + pro + nōbīs, dative of nōs, 1st person plural pronoun.