Abraham and Christmas

Respondit Jesus, Abraham exsultavit ut videret diem meum; vidit, et gravisus est. Ille, ut ostenderet vivere Abraham, dixit illum vidisse diem suum, id est diem quo mundo natus est Christus. Dierum conditor non tenetur die, temporis auctor tempora nescit; sed Christus propter hominem homo natus, et diem suscepit et tempus. 'Abraham exsultavit ut videret diem meum.' Si Moyses et Elias in monte occurrunt, ut promissum conspicerent Christum, quomodo nec Abraham occurrit ad partum Virginis, ut promissam benedictionem in gentibus, id est, in semine suo, patientissimus exspectator intenderet? Sanctus Petrus Chrysologus, Sermo CXXXI

Jesus replied, 'Abraham rejoiced that he was to see my day; he saw and he was happy.' 1 He, that he might show Abraham lived, said that he had seen His day, that is, the day on which Christ was born to the world. The Creator of days is not constrained by the day, the Author of time does not know periods of time. But for the sake of the human being Christ was born a man and became subject to both day and time. 'Abraham rejoiced that he was to see my day.' If Moses and Elijah are present on the mountain that they might catch sight of the promised Christ, 2 what prevents Abraham from being present when the Virgin gives birth, so that after waiting patiently he might behold the blessing promised in his people, this is, his seed? Saint Peter Chrysologus, Sermon 131 1. Jn 8. 54, 56.52 2  Mt 17.3