This article discusses the Passover feast, the feast of weeks (feast of harvest/Pentecost), and the feast of booths. The author discusses how these three feasts were celebrated in the Old and New Testament and how they point to Christ.
The sin of the golden calf resulted in God revoking (Numbers 3:12-13) His previous blessing (Exodus 13:2) of allowing the Israelites' firstborn sons to serve in the Tabernacle as priests. These sons were replaced by the Levites. In Christ this curse was removed.