'A shekel' signifies the price or estimation of good and truth, and 'half a shekel' signifies the determination of the quantity thereof.

(References: Arcana Coelestia 3104)

10313. The spirits belonging to our planet declared that they did not dare to go near them because, when they did so, not only were they seized with anxiety, but also they experienced the delusion of being bound hand and foot to serpents, from which they could not be released until they moved back. Such a delusion is due to correspondence. For a person's physical senses are represented in the next life by serpents, and therefore also in the Word the level of the senses, which is the last and lowest of a person's life, is meant by 'serpents'.