The number 66 is linked in the Bible to the number of people in Jacob's family who went to Egypt, and to the purification period after the birth of a daughter.
The number 66 appears at two important occasions in the books of Moses. In Genesis 46:26 it is mentioned that 66 persons from Jacob's household came to Egypt, excluding Jacob's daughters-in-law. This number represents the people of Israel during a decisive transitional phase – the journey from Canaan to Egypt, which inaugurates a new epoch in salvation history where God's people are to become a great nation in a foreign land. In Leviticus 12:5 it is established that a woman who gives birth to a daughter shall remain at home for 66 days in her blood of purification, after an initial two weeks of uncleanness. This period of purification is twice as long as for a son, which has been the subject of extensive rabbinic discussion. Overall, the number 66 appears in contexts concerning transition and sanctification – Israel's transition to Egypt and the woman's transition back to ritual purity. The Protestant Bible canon contains 66 books (39 in the Old Testament and 27 in the New Testament), which in Christian tradition is often understood as an expression of the completeness and wholeness of Scripture. In Jewish gematria, the number 66 has no prominent independent role, since it does not correspond to any central Hebrew word or concept of particular symbolic significance. The rabbis have discussed why the purification period in Leviticus 12 is twice as long for a daughter as for a son. Various explanations have been proposed, including that the daughter herself will one day undergo childbirth and purification.*