John Barling rarely appears in the book, but he's certainly got the whole town of Lily, Arkansas, stirred up over his supposed sighting of the Lazarus bird. For the record, Lazarus is a dude from the Bible whom Jesus raised from the dead (how's that for a party trick?)—and the bird Barling claims to have seen has been considered extinct for a while. So that's that biblical reference.
Cullen and his friends despise John because they believe that he is just seeking attention, and in doing so, taking the town's focus off of Gabriel's disappearance:
Fulton Dumas […] described John Barling as the most egotistical, maniacal, and power-hungry man he'd ever met. I didn't put too much stock in what Fulton said, given that the only man he had to compare anyone to was his slightly effeminate father. But when I saw John Barling and heard him talking about finding the Lazarus, I knew Fulton had been spot-on. (5.2)
Even though everyone else in the town buys into Barling's big woodpecker sighting, Cullen is wary of him. And in the end, he's proven right—Cullen is correct that Barling is a farce. Insofar as we're hanging out in biblical-reference-territory, here we can see parallels between Barling and Jesus himself. Just like Cullen doesn't like Barling and would like to see his fifteen minutes of fame end, so, too, did the religious authorities of the time wish Jesus would hurry up and leave already.
Cullen fares considerably better than the religious authorities when it comes to his desire for the Jesus (figure) in his life to bounce. But this is because Barling falls pretty short of Jesus. Whereas Jesus actually resurrects Lazarus, the bird Barling purports to have found long after its presumed extinction turns out to be, well, extinct. Just like Barling's claim to fame. Oops.