Omer counting,

50 days from 2nd day of Passover to the day of Pentecost

Leviticus 23:15-22;

And you shall count for yourself from the day after the Sabbath, from the day that you brought the sheaf of the wave offering: seven Sabbaths shall be completed.

Count 50 days to the day after the seventh Sabbath. then you shall offer a new grain offering to the Lord.
The word count to 50 in this passage , meaning to get yourself involved in the relationship as you eagerly wait or count yourself in the promise that has been promised to take place on the 50th day.

You started the counting for only one reason; and the reason is that you may get to that last number of your counting.
It is just like somebody saying to you; I have a job for you; and then you will say to him; How much am I getting paid for that?

You are doing something, but also at the same time counting is taking place, so that you may reach to that desired number or amount of your salary.

The day of Pentecost.
The word Pentecost meaning: a feast or a joyful time or moment that is held on the 50th day, in Hebrews it is called Shavout, meaning the Feast of Weeks or the feast that is held after the counting of the seven weeks.

In the book of Acts 1:4-5, Jesus (Yeshua) our Lord commands his disciples to depart not from Jerusalem, but to wait and count until when that 50th day comes.
The day when their promise of the Father fell upon their lives, the day when the strenght of the Holy Spirit is given.

From the 2nd day of Passover we give an Omer offering into God's work to reveal to God that we are involving ourselves into this powerful counting that takes place within these seven weeks, beginning from the 2nd day of Passover in the first month of Nissan to the 6th day of the month of Sivan, which is the 3rd month according to the Hebrew calendar, or I rather call it God's calendar.