In the ancient world, and I am talking like the first books of the Old Testament here, pre-Illiad, Epic of Gilgamesh stuff, it was common practice for an army to march into battle with a statue of their god. In some cultures the statue was just a symbol, while other cultures believed the god lived inside of it. Another common practice was that the victor of the battle would carry away the statue as part of the spoils, literally saying ‘my god is better than your god’. And at times these statues were so invaluable to the society that the plundered city put priority on recovering the statue over rebuilding, like when Assyria destroyed Babylon in the Bible.
It may seem silly to us now, clearly no god was ever in any of those statues. They were, at best, symbols of a higher power, and could easily be remade. But the concept of holding man-made constructions of man-made ideas precious still resides deep within us. Why does burning a flag matter so much? Why do people ‘swear to god’ or on a Bible? Why are often the most effective military targets the largest cultural ones?