Mark Boykin of Church of All Nations in Boca Raton, told CBS 12 the structure represents the "essence of evil" and is an "insult to the city".
Preston Smith, who is a local teacher, submitted an application to the city to erect the giant monument, which features a six-foot-tall pentagram painted red with a wooden image representing Satan in the middle of it.
He also intends to put up a "Freedom from Religion Nativity Scene" to replace a traditional nativity scene - complete with the Baby Jesus in a manger and the Virgin Mary - set up by churches.
Boykin said: "In essence they're putting out a welcome mat for Satan.
"I will take the responsibility for taking the sledgehammer and knocking it down."
The display, weighing 300 pounds, includes phrases such as: "In Satan We Trust", "One Nation under Antichrist" and "May the Children Hail Satan".
The pastor's disproval has been echoed by city officials but they have expressed the need to enable free speech.
Susan Haynie, Boca Raton Mayor told CBS 12: "I find this extremely offensive. But you know, again, we've chosen as the council to honour free speech."
Scott Singer, a Boca Raton city council member reiterated this point and said: "This is not consistent with my particular values, but free speech means people have an opportunity to express themselves, whether government likes it or not or whether individuals like it or not."
The monument and alternative nativity scene is set to be on display at Sanborn Square on Federal Highway in Boca Raton from 1st December and not taken down until 6th January 6, 2018.
