What did the observance of the sabbath look like during the intertestamental period?
Judaism began to divide into two strands. A more mystical and spiritual approach was found in Hellenistic circles. According to Philo, the sabbath was not intended for emptiness, but was to be devoted to spiritual studies. Palestinian Judaism, on the other hand, took a more literal or rigid approach that developed a stereotyped code specifying what could or could not be done. For example, the rescue of an animal from death was forbidden. Yet, certain practices were permitted such as priests serving in the temple, emergency life saving, and circumcision on the eighth day.
Despite burdensome restrictions, the sabbath was to be joyful, celebrated at home with rest and refreshment and corporately in public worship. Everything had to be prepared the day before, which in Jewish usage was on Friday, and the lamps lit at sunset. In the Didache, it was seen as a fast day, marking the death of Jesus. An extra meal was added to the normal two meals, the best clothes were worn, and guests invited. According to the Babylonian Talmud Pesahim, one half of the day was devoted to eating and drinking and the other half was dedicated to instruction in the things of God.
Source: Brown, Colin, General Editor, The New International Dictionary of New Testament Theology, Vol. 3, Grand Rapids: MI, 1986, pp. 407-408.