The Transfiguration of Christ and how it contributes to understand the Holy Trinity. Read that scene slowly, and the tritheism charge does not survive it — but neither, and this is the part the sceptic never expects, does the charge's mirror-image twin, the lazy shorthand that treats “God” as a single actor who occasionally puts on different hats. Both errors die on that mountain. That is rather the point of putting it there

Raise your hand if you've ever sat in a pew, a Sunday school class, or a late-night dorm room conversation and thought: "The Holy Trinity? Sure. Absolutely. Three-in-one. Totally got it." — while absolutely not getting it. 😂

Don't worry. You're in excellent company. Theologians have been wrestling with the doctrine of the Trinity since the Council of Nicaea in 325 AD, and the debate has been lively enough to make modern Facebook arguments look like polite tea parties. In fact, one bishop reportedly punched another bishop in the face over it. At a church council. Which, when you think about it, is an extremely committed way to do theology.