As an exercise in illustrating the idea her class are asked to come up with an example of “three things in one” that go to make up a whole which, as I have contemplated the task, is a lot harder than it sounds. Coming up with a gestalt of three things is relatively easy and my best effort is a song; which comprises rhythm, melody and lyric as distinct elements that combine to make for one coherent auditory experience yet can also be experienced and understood separately. I am told the example often given to the pupils is a Mars bar (chocolate, nougat and caramel in one), but neither really addresses the concept of the Trinity satisfactorily, because for that each individual element must also be complete in its own right and not only represent, but be the whole.
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There is in fact very little biblical support for the idea of the Trinity. Genesis has references to God in the plural (Elohim), which some theologians claim as a Trinitarian reference but more likely reflects the polytheist nature of early Judaism. Later writings such as Isaiah portray God in firmly singular terms and the New Testament is similarly lacking in clear references.
What the early Church appears to have done is create a deity with multiple personality disorder purely for the expedient of avoiding accusations of polytheism (a charge which even so is laid by Muslims on Christianity) while allowing the simultaneous worship of Jesus and Yahweh.
Ultimately believers present the irrationality of the Trinity as a divine mystery that defies human understanding so we shouldn’t be surprised that explanations are hard to come by, but this of course is the hallmark of all religious apologetics; if it doesn’t appear to make sense it is just good old ineffable God and his funky mysterious ways bless him.
If a chocolate sweet can really represent the Trinity, it’s probably a Fudge.