A study of the wide spectrum of theological views on the Sabbath in the Jewish and Christian faiths of antiquity; In A Day of Gladness, Herold Weiss compares the ways in which Christians and Jews of antiquiry viewed the Sabbath. Rather than attending to the minutiae of its observance among Jews or its connection with Sunday observance among Christians, he examines major extant texts for the fundamental religious concerns of their authors and communities, particularly how those concerns shaped their thoughts about the Sabbath. Weiss contends that the wide spectrums of theological beliefs illustrate the internal diversities of these two faiths as well as their commonalities. To explore Jewish perspectives, Weiss looks to the Rabbinic and Qumranic texts, Samaritan texts, and the writings of Philo and of Josephus. To illumine early Christian attitudes, he offers analyses of the Synoptic Gospels, the Gospels of John and Thomas, and the letters to the Galatians, the Romans, the Hebrews, and the Colossians. Weiss uses each text as a window upon the sociological constructs and theological perspectives figuring in early Jewish and Christian thought about worship and rest. He suggests that such perspectives reflect larger theological postures because, as an element of the creation story, the Sabbath became an important cosmological fixed point and a source of eschatological speculation. With insights gained from his examination of the texts, Weiss identifies the concerns animating Sabbath disputes. He marks out in the beliefs of Jews and early Christians overarching similarities between the two faiths as well as variations within each.