Can a character that isn't a cleric (or a paladin, etc) wear and gain the benefits of a holy symbol? Of course, since most holy symbol powers trigger on making an attack, most holy symbols would be useless to a character who can't use them as an implement. However, there are a few notable exceptions, such as the Symbol of Hope from the PHB:
This would be useful to anybody, especially since it goes in a "free" item slot. It seems "wrong" to let a Wizard or something wear this thing and use it, but the CB lets it be equipped and I can't find anything against doing so in the rules. It's clear that the Wizard wouldn't be able to attack with the symbol, but is there anything in the rules against him wearing it and using the power?Symbol of Hope
Power (Daily): Immediate Reaction. You can use this power when you or an ally within 5 squares of you is hit by an effect that a save can end. You or the ally gains a +5 power bonus to saving throws against the effect.