The Feast of Weeks followed the Feast of Firstfruits. During the Feast of Weeks, the priest made a wave offering to the Lord, and then the Lord said,
“And you shall count for yourselves from the day after the Sabbath, from the day that you brought the sheaf of the wave offering: seven Sabbaths shall be completed. Count fifty days to the day after the seventh Sabbath; then you shall offer a new grain offering to the LORD” (Leviticus 23.15).
Sevens in the Bible 
Preacher Don,
You write, “For example, Premillennialists do this with worldwide events, somehow working that event into Scripture as a sign of the return of Christ”. Check this comment, click http://www.biblebuslimericks.com/backend/bybible.php.
Jim Burgoon
Pastor Don,
Sorry about that. The URL link should have been http://www.biblebuslimericks.com/limerick.php?id=3134.
Jim