PoserWorld is a subscription site, but it's well worth it. You can download everything they have if you buy even the cheapest subscription.

Anyways, they have a set of Biblical clothes that might be what you're looking for. For men and women. Sandals, gown, robe, sash, headdress. I think the male stuff is for the P4 male, which is included with Poser.

They also have a flowing toga-type for Michael 1, that might make a good Jesus costume if slightly re-textured.