In which seasons did Israel celebrate Passover and the Day of Atonement?
Israel celebrated Passover in the spring, as a memorial of the night in Egypt when the death angel passed over and they were protected by the blood. The Day of Atonement, later called Yom Kippur, was celebrated in the fall. Leviticus 16 discusses it, though the term Atonement is a misnomer since animal blood could not take away sin.
Les explains that these Feast Days, including Passover and the Day of Atonement, began shortly after Israel came out of Egypt. Passover was the spring Feast, a memorial of the night in Egypt when the death angel flew over and the people were protected by the blood. The Day of Atonement was in the fall and is known in English as Yom Kippur, which Les says is a far better definition than Atonement. He notes that Atonement is really a misnomer in Leviticus, because there was no atonement—animal blood could not take away sin. The word can be split into At-one-ment, which is a good definition.