You might find it interesting then (and I love to study this stuff) that it was 50 days after Israel was led out of Egypt that they recieved the law at Mt. Sinai. That was when they rebelled and made the golden calf. Moses came down from the mountain and on seing their disobedience, commanded the levites to kill those who worshipped the calf.
When Moses realized that, to the scornful joy of their foes, Aaron had let the people run wild, he stood at the gate of the camp and cried, “Whoever is for the LORD, let him come to me!” All the Levites then rallied to him, and he told them, “Thus says the LORD, the God of Israel: Put your sword on your hip, every one of you! Now go up and down the camp, from gate to gate, and slay your own kinsmen, your friends and neighbors!” The Levites carried out the command of Moses, and that day there fell about three thousand of the people. (Exodus 32:25-28)
Note that 3000 people fell that day.
Peter (said) to them, “Repent and be baptized, 7 every one of you, in the name of Jesus Christ for the forgiveness of your sins; and you will receive the gift of the holy Spirit. For the promise is made to you and to your children and to all those far off, whomever the Lord our God will call.” He testified with many other arguments, and was exhorting them, “Save yourselves from this corrupt generation.” Those who accepted his message were baptized, and about three thousand persons were added that day. (Acts 2:38-41)
Note that on Pentacost, the killing of 3000 at Mt. Sinai was reversed. 3000 people were instead added that day!
Pentacost is a reversal of Israel’s rebellion brought about by their inablity to trust God. Having spent several centuries in slavery, who can blame them for not being able to trust God. They had to relearn everything and that is what most of the OT is all about, Isreal relearning how to trust God. Pentacost caps off that learning process. God’s Church, his visible instrument of salvation in the world is created, and man can now trust God again.
I also note with more than just passing interest how both Moses and Peter are clear leaders during these decisive moments. The parallels are clear to me.
Sorry to swerve off topic and if you know this already.
-Tim-