This vessel belongs to a particular group of glass vessels bearing Jewish or Christian motifs that were manufactured during the Byzantine Period (a third group is decorated with "neutral" motifs of unknown meaning).
Israeli asserts ("Eulogia vessels" in Israeli, et al., Ancient Glass in the Israel Museum, p. 270-271) that such vessels, mainly hexagonal or octagonal in shape and amber brown in color, were produced in the Holy Land likely by the same workshop, and perhaps used by pilgrims for acquiring oil, earth or water from holy sites.
For similar examples see nos. 361-363, in Israeli, et al., op. cit., and no. 173 in Stern, Roman Mold-blown Glass, the First through the Sixth Centuries.