18 When the heavens were serene and earth was silent and night lay on the world, in secret, far from the crowd of men, the Eternal Word of the Father, having assumed the nature of man, appeared to mortals, and the heavenly regions echoed the heavenly hymn, "Glory to God in the highest and on earth peace to men of good will." This praise of Christian peace - the Peace of Christ in the Kingdom of Christ - setting forth the supreme desire of Our Apostolic heart to which all our aims and our labours are directed, nearly touches the minds of Christians who withdrawn from the tumult and the vanities of the world in deep and hidden solitude have pondered on the truth of faith and the example of Him who brought peace to the world and left it as a heritage: "My peace I give to you."
Source: Mens Nostra (Vatican.va)