|Malloch the Saved|
|Paladin of Baha-who?|
Knowledge (religion) to know what an altar (note spelling) to your God would require. Craft(carpentry) to build a wooden altar, Craft(stone) to build a stone one. If you don't have a craft skill but you make the religion check (which shouldn't be hard, probably a DC10) you can probably make a makeshift altar out of basic materials at hand.