Aclergyman is an official leader within an organized religion. why does dickinson call god “a noted clergyman” in "some keep the sabbath going to church"?

A clergyman is "a male priest, minister, or religious leader, especially a Christian one."

She is trying to create a mild fun by saying that God is "a noted clergyman."

Explanation:

Emily Dickinson in her poem "Som Keep The Sabbath Going to Church" exerts the point that some people still keep going to Church on Sabbath day(a Holy day of worshiping God according to Christian belief). But she stays at home and write, which is her religion, her way of worshiping.

In third stanza, Dickinson calls God a clergyman,

"God preaches, a noted Clergyman-

And the sermon is never long,

So instead of getting to Heaven, at least-

I'm going, all along."

As she does not go to church on Sabbath, she is saying that God preaches to her. Making a point that God is present everywhere. So, if she does not go to church God visits her home and gives short sermon just like a clergyman gives in the church.