Have you been counting the omer? This is a command by God found in Leviticus 23.
Leviticus 23:15-16 (KJV)
And ye shall count unto you from the morrow after the sabbath, from the day that ye brought the sheaf of the wave offering; seven sabbaths shall be complete:
Even unto the morrow after the seventh sabbath shall ye number fifty days; and ye shall offer a new meat offering unto the LORD.
Most Christians have never even heard of the omer, much less the counting of it. Yet, here it is, right after the description of the Feast of First Fruits. In fact, the Feast of First Fruits is the beginning of the counting. Verse 15 refers to the Feast of First Fruits as the morrow after the sabbath, the day that the Jewish people were to bring the first sheaf of barley to be waved before the Lord. This counting was to continue until seven sabbaths were counted. This equals 49 days (7x7). Verse 16 then concludes that on the following day, the 50th day, a new grain (meat as in meal) offering would be made unto the Lord. This would be an offering of the wheat harvest.
Can you guess what day is the 50th day after the Feast of First Fruits? It is the Feast of Weeks or Pentecost! This feast is one that most Christians are very familiar with given the events of Acts chapter 2 and the coming of the Holy Spirit.
The counting of the omer connects the Feast of First Fruits and Pentecost. But what is an omer? An omer is a measure of about 3.64 liters. The idea was to bring the first sheaves of the barley harvest to the priest to be waved before the Lord. So the command is basically to count a sheaf of barley every evening until Pentecost. Traditionally, the counting began on the 16th of Nisan. (Remember the Passover lambs were to be killed on the 14th.) Today, we simply count the days, since the Temple has been destroyed and we can't physically perform the required offerings. But the counting is still called, "the counting of the omer."
The traditional count, done in the evening, is accomplished by saying something like the following:
"Blessed are you, O Lord, our God, King of the Universe, who has sanctified us with His commandments and has commanded us regarding the counting of the Omer. Today is the (whatever day, eg. fifth) day of the Omer."
After Yeshua was raised from the dead on the Feast of First Fruits, He spent 40 of the 50 days teaching the disciples. After that, Yeshua ascended into Heaven and told the disciples to wait in Jerusalem until the coming of the Holy Spirit, which occurred on Pentecost, the 50th day.
If Yeshua meant those days to be a type of preparation we should continue to remember them.