The centre of Yahweh's worship lay in three great annual festivals coinciding with major events in rural life: Passover with the birthing of lambs, Shavuot with the cereal harvest, and Sukkot with the fruit harvest. These probably pre-dated the arrival of the Yahweh religion, but they became linked to events in the national mythos of Israel: Passover with the exodus from Egypt, Shavuot with the law-giving at Biblical Mount Sinai, and Sukkot with the wilderness wanderings. The festivals thus celebrated Yahweh's salvation of Israel and Israel's status as his holy people, although the earlier agricultural meaning was not entirely lost. His worship presumably involved sacrifice, but many scholars have concluded that the rituals detailed in Leviticus 1–16, with their stress on purity and atonement, were introduced only after the Babylonian exile, and that in reality any head of a family was able to offer sacrifice as occasion demanded. A number of scholars have also drawn the conclusion that infant sacrifice, whether to the underworld deity Molech or to Yahweh himself, was a part of Israelite/Judahite religion until the reforms of King Josiah in the late 7th century BCE. Sacrifice was presumably complemented by the singing or recital of psalms, but again the details are scant. Prayer played little role in official worship.