*can't believe he's actually chiming in on this*
I think one of the key things to keep in mind for this concept is that traditionally, objects of power function in a completely different manner in most fantasy than the biblical examples Jonathan mentioned. Objects of power in fantasy typically function like batteries, they hold some awesome power that the character controls. But the bronze serpent and the Ark of the Covenant were more like physical channels for God's power (for lack of a better way to word it). Their power wasn't just there for the taking.
The best example of this is in the book of I Samuel, where the Israelites take the Ark of the Covenant into battle with them, believing that it will grant them victory. They were defeated and the Ark of the Covenant was captured. See, the Ark of the Covenant served a specific purpose, it was a physical symbol of God's presence among his people. But the Israelites tried to manipulate God's presence and get him to do things their way and it didn't work. But not to have his name be tarnished, God then struck down the Philistine idols that the Ark was stored next to and inflicted the Philistines with tumors as a sign for them to know that He was not to be trifled with. When God chose, he worked his power in the presence of the Ark of the Covenant, but only when he chose. Similarly, the Bronze Serpent only healed the sick on that one specific occasion.
In fact, one could say (and I'm sure there are those that have said it) that the Serpent and the Ark had no power, imbued or otherwise, but that God worked his power in their vicinity and used them as visual reminders for his people. Yes, Sam, I know you disagree with that view, and you've made that perfectly clear in earlier posts, so need to rise up in rebuttal. Or one could say (like I tried to earlier in this post) that God channeled his power through the Ark and the Serpent on specific occasions, and that outside of those occasions, they had no power. Or you could go along with the notion that they had power that God imbued in them, but keep in mind that even in that case, it was still only available on His terms for His purposes. Honestly, I think advocating any of these views too strongly is a bit frivolous, because honestly, it's not something we can prove. As long as the main point that God used these objects to further his purposes and demonstrate his power is understood, I think you're free to believe whatever you want about how exactly he used them.
Now, for Objects of Power in Fantasy, there are actually two different ways to handle them. Ok, technically there are three, but whatever
The first is through Cobha. The objects, just naturally have their power. Obviously their powers still come from God, because He created everything and wrote the laws of Cobha for that world. But that's different than the Ark of the Covenant and the Bronze Serpent because in those instances, He specifically communicated that the objects were going to have power and that it would be His power at work.
Which leads us to approach number two, in which God specifically uses the object of power to further his purpose and demonstrate His power, love, etc. And if this is the case I think there are a few ideas we glean from the Ark and the Serpent:
- God did it for a reason. He didn't just say, "You, know Mo, yall should build a fancy box, coat it with gold, and I'll give it special powers for the fun of it." Now, of course, he's not a tame lion, so in your world maybe he does do that
- He communicated very clearly that the power was coming from Him and why He was doing it. He didn't leave it up to the imagination. The Ark didn't suddenly appear and start glowing without any explanation. The only times that God worked his power through the Ark without first giving instructions were when the Ark was captured by the Philistines and when Uzzah touched the Ark and died instantly.
- God was driving. Like I mentioned at the beginning, the power wasn't just there for people to use willy nilly. The Ark and the Serpent were God's calling cards (so to speak) and as such, they only did spectacular things when He willed it.
- In the event that people got off track and started focusing on the power or the object more than the source (aka God), God pulled the plug. He's a jealous God and is not about to be upstaged by His tools.
These are just observations, but if your writing is going to portray God acting directly in your world, then it would be wise to maintain a healthy level of consistency with the biblical records of His activities.
And the third approach is that a created being imbued the object with his/or her own power. Technically, this is a subset of the first approach, because whatever power they have, they have through cobha (aka God gave it to them). But the difference is that the object has power not because of natural/cobhaic properties, nor because God himself reached down and gave it power, but because somebody else gave it power.
Now to clarify, I'm not saying that this is an either-or scenario. I don't think you have to stick with one approach for every object of power in your world. Rather, what I'm saying is when you want an object in your rule to have cool abilities, these are three main ways it could happen. And I think having all three in your world would be awesome!

Now as for other examples of God working miracles through objects in the OT, there's jar of oil and jar of flour in I Kings 17 that never ran out as long as the drought lasted. Then there's similarly the widow's jar of oil in II Kings 4 that kept miraculously refilling long enough to fill a bunch of other jars with oil to sell. And there's the bones of Elisha that brought a dead man back to life when he was tossed in Elisha's grave. And you could almost include Elijah's cloak which he used to part the waters of the Jordan and which fell to Elisha as Elijah was ascending in the whirlwind, but honestly, that was more of a symbol of God's approval than it was an object of power IMHO.
Sorry for the long post, I really thought it was going to be shorter than this or I wouldn't have started replying to the thread at all
