However, leave it to the Supreme Court to get into the act! In 1947, in Everson v. Board of Education, the Supreme Court first cited the phrase, “wall of separation between church and state” from a letter by Thomas Jefferson to the Danbury Baptist Association. Now we have the Baptists getting into the mix as well!
“While the Supreme Court did rule that a “wall of separation between church and state” exists, they did so based upon seven words from one personal letter rather than from the Constitution. As a result, the Supreme Court created an erroneous precedent, ruling that law could be created from a personal letter instead of the Constitution.”
https://www.theunion.com/news/twi/no-such-thing-as-separation-of-church-and-state/