“This is the covenant I will make with the people of Israel after that time,” declares the Lord . “I will put my law in their minds and write it on their hearts. I will be their God, and they will be my people. -Jeremiah 31:33 "The festival of Shavuot is a Jewish holiday that occurs on the sixth day of the Hebrew month of Sivan (late May or early June). Shavuot commemorates the anniversary of the day God gave the Torah ( or the law) to the entire Israelite nation assembled at Mount Sinai, although the association between the giving of the Torah (Matan Torah) and Shavuot is not explicit in the Biblical text. Shavuot follows Passover by 50 days." ' ( from https://www.hebcal.com/holidays/ shavuot) This is where we get the celebration of Pentecost. It is no wonder that the outpouring of God's Holy Spirit was on this day- 50 days after Passover, of which Christ was the Passover lamb. In Jeremiah...
"The word is near you; it is in your mouth and in your heart, so you may obey it." Deut 30:14