Let’s kick off Chapter IV, “Dies Hominis,” the day of humankind. Sunday is a day of joy, rest, and solidarity, according to the subtitle of the chapter heading. First consideration: “The ‘full joy’ of Christ.” This is an ancient tradition, and not confined to Roman tradition:
55. “Blessed be he who has raised the great day of Sunday above all other days. The heavens and the earth, angels and of men give themselves over to joy”.( This is the Deacon’s proclamation in honour of the Lord’s Day: cf. the Syriac text in the Missal of the Church of Antioch of the Maronites (edition in Syriac and Arabic), Jounieh (Lebanon) 1959, p. 38) This cry of the Maronite liturgy captures well the intense acclamations of joy which have always characterized Sunday in the liturgy of both East and West. Moreover, historically — even before it was seen as a day of rest, which in any case was not provided for in the civil calendar — Christians celebrated the weekly day of the Risen Lord primarily as a day of joy. “On the first day of the week, you shall all rejoice”, urges the Didascalia. (V, 20, 11: ed. F. X. Funk, 1905, p. 298; cf. Didache 14, 1: ed. F. X. Funk, 1901, p. 32; Tertullian, Apologeticum 16, 11: CCL 1, 116. See in particular the Epistle of Barnabas, 15, 9:SC 172, 188-189: “This is why we celebrate as a joyous feast the eighth day on which Jesus was raised from the dead and, after having appeared, ascended into heaven”) This was also emphasized by liturgical practice, through the choice of appropriate gestures. (Tertullian for example tells us that on Sunday it was forbidden to kneel, since kneeling, which was then seen as an essentially penitential gesture, seemed unsuited to the day of joy. Cf.De Corona 3, 4: CCL 2, 1043) Voicing an awareness widespread in the Church, Saint Augustine describes the joy of the weekly Easter: “Fasting, is set aside and prayers are said standing, as a sign of the Resurrection, which is also why the Alleluia is sung on every Sunday”. (Ep. 55, 28: CSEL 342, 202)
Today, we know of the reticence in some quarters of fasting on Lenten Sundays. But we still restrain ourselves from singing Alleluia.