[Uri’el-2012]

and you can see there was a church, with a specific structure of leaders that were called by God to lead the church. This is the Catholic definition of church. Now, if the church is founded upon the leaders then it is safe to say that “the church” can also mean “the leaders” or “the one’s with teaching authority” called the Magisterium.

Or is it all those called out by YHvH ?

A study of the word "church", in the Koine Greek : Ekklesia.

Was the "church" started at the YHvH commanded
Feast day of Shavuot (pentecost) as some say ?

or

Did the "church" exist earlier ?

Using the LXX as a guide we see that the Ekklesia
is first used in Deuteronomy 4:10

NAsbU Deuteronomy 4:10 "Remember the day you stood before the LORD your God
at Horeb, when the LORD said to me, 'Assemble the people to Me, that I may let
them hear My words so they may learn to fear Me all the days they live on
the earth, and that they may teach their children.'

Also see : Deu 4:10, Deu 9:10, Deu 18:16, Deu 23:3, Deu 23:4, Deu 23:9, Deu 31:30,
Jos 9:2, Jda 20.2, Jda 21:5, Jda 21:8, Jdg 20:2 Jdg 21:5, Jdg 21:8, 1 Sa 17:47,
1 Sa 19:20, 1 Ki 8:14, 1 Ki 8:22, 1 Ki 8:55, 1 Ki 8:65, 1 Ch 13:2, 1 Ch 13:4, 1 Ch 28:2,
1 Ch 28:8

shalom b'SHEM Yah'shua HaMashiach

[The Ignorant Fisherman]

It’s all Jewish my friend.... That is the window in which we must all look through for proper understanding and insight into the Holy Scripture’s.. led acourse by the Ruach HaKodesh!