It’s not religious.
“It’s a rather joyous song,” Cohen said on the release of “Various Positions,” and, he argued often, a secular one. He wanted to push the words of praise back to Earth, “to indicate that Hallelujah can come out of things that have nothing to do with religion.” - The Holy or the Broken: Leonard Cohen, Jeff Buckley, and the Unlikely Ascent of ‘Hallelujah’ by Alan Light
Hallelujah-Leonard Cohen