Revealing mistake: During Bartleby's "Prepare to taste God's wrath" diatribe, you can clearly see the seam along the front of his shirt that he uses to tear his shirt open revealing his armour. This seam is not seen at any other point in the movie.
Revealing mistake: During the final battle with Bartleby, when he turns to face the church/group, we can see Loki lying dead on the ground with his legs spread. At this point Loki moves his foot to a more comfortable position.
Revealing mistake: Bethany gets upset about finding out she's related to Jesus and goes in the water to scream at God. Metatron is instantly there. He walks across the water. You can see the supports underwater that he is standing on. Look to the left of him.






Chosen answer: What he means is that humans have the choice to accept or reject God's love, but that angels have no such choice. Lucifer questioned this logic and was prompted to start a war, just as they're questioning it and are prompted to find a loophole to return to Heaven.
Captain Defenestrator