With the exception of Purim, postexilic feasts are not presented in the Old Testament. For the most part, they developed in the intertestamental period and are mentioned primarily in the books of the Old Testament Apocrypha.
Three national festivals were celebrated yearly in the temple: Passover, the Feast of Weeks, and the Feast of Booths.
Although the Lord had granted the covenant to the patriarchs of Israel, the covenant at Mount Sinai was a new departure in the people’s relationship to God. The covenant established the structure of the worship of Israel as a distinct people and formed the basis for the prophetic word and the ongoing religious life of the community.
Biblical worship is corporate. The worshiper comes to God as a part of a larger community bound to the Lord in covenant and celebrating in festal assembly.