He originally wrote 80 verses to this song but narrowed it down to 4 for the recording. Halleluiah basically means "Joyfully praise the Lord" but he extended that beyond the religious meanings. Cohen said: “This world is full of conflicts and full of things that cannot be reconciled,” Cohen has said, “but there are moments when we can transcend the dualistic system and reconcile and embrace the whole mess, and that’s what I mean by ‘Hallelujah.’ That regardless of what the impossibility of the situation is, there is a moment when you open your mouth and you throw open your arms and you embrace the thing and you just say, ‘Hallelujah! Blessed is the name.’… “The only moment that you can live here comfortably in these absolutely irreconcilable conflicts is in this moment when you embrace it all and you say, ‘Look, I don’t understand a fucking thing at all – Hallelujah!’ That’s the only moment that we live here fully as human beings.” Even though I don't care much for Rolling Stone they do have a good write up on the song: https://www.rollingstone.com/feature/how-leonard-cohens-hallelujah-brilliantly-mingled-sex-religion-194516/