Some people think that weddings and religion go hand-in-hand.
This isn't always the case. Some couples aren't religious, and others might be spiritual but not identify with a specific faith. A present that's religious in nature might sour on a couple who doesn't understand or appreciate it or -- even worse -- who think the giver is trying to impress his religion on them. An icon or statue from outside of a couple's faith will only catch dust in their home.
The gift of religious texts can also be offensive to the bride and groom and embarrassing for the gift-giver. As with artwork, it’s imperative to know the couple extremely well if you're considering giving them a religious gift. If you have any doubts, defer to the registry!