In the third month, when the children of Israel were gone forth out of the land of Egypt, the same day came they into the wilderness of Sinai.
All Commentaries on Exodus 19:1 Go To Exodus 19
Augustine of Hippo
AD 430
We come now to the desert, where the law was given, and this is what Scripture says: “But in the third month from when the people were brought out of Egypt.” The Lord spoke to Moses that those who were going to receive the law should purify themselves in readiness for the third day, on which the law was to be given. So at the beginning of the third month a purification is commanded in readiness for the third day. ..
