EXCLUSIVE

Members of an Indiana church say they've been flooded with death threats since video of a 3-year-old proudly singing, "Ain't no homos gonna make it to heaven" ... was posted on the Internet.

Multiple members of the Apostolic Truth Tabernacle Church in Greensburg, Indiana tell TMZ the church office has been getting harassing calls and the pastor has received death threats at his home. They also say a prayer meeting scheduled for this evening at church had to be moved to a secret location.

We're told they are looking into increasing security, but for now the congregation is handling it ... taking turns watching over the church.

One member says Pastor Jeff Sangl is extremely worried about his safety -- and this morning he and his wife left for vacation without telling anyone where they were going.

Despite the threats, all the members we spoke to have no regrets about the song getting posted online -- in fact one said, "The people who are upset just don't read the word of God. If we don't teach the children the truth early they will never learn."