If you're referring to Ishmael from the Old Testament, that would be Judaism or early Christian. The name also figures in Islamic history.
If you're referring to the character Ishmael from Moby Dick, he was a mid-19th century American from Manhattan with a biblical name, so presumably, he too, was a Christian.
Ishmael went to sea aboard a whaling ship in the novel "Moby-Dick" by Herman Melville. He joined the crew of the ship Pequod under the command of Captain Ahab to hunt and seek revenge on the white whale, Moby Dick.
Ishmael Furoz goes by Ish.
St Daniels College
Ishmael Butler goes by Butterfly, and Ish.
References to Ishmael in the Bible can be found in the books of Genesis and Galatians. In Genesis, Ishmael is the son of Abraham and Hagar, while in Galatians, he is used as an allegory for the slave woman in contrast to Isaac, who represents the free woman.
Ishmael's mother was Hagar, Abraham's maid-servant.
My Ishmael was created in 1997-12.
Ishmael Khaldi was born in 1971.
Ishmael Flory was born in 1907.
Ishmael Flory died in 2004.
Ishmael Noko was born in 1943.
Odeen Ishmael was born in 1948.
Ishmael Jones was born in 1961.