The Cross is certainly a compelling fact. Facts describe what and when and at what rate, but facts don’t necessarily offer a why, which in terms of the Cross constitutes mystery. Mystery doesn’t necessarily mean “un-knowable”, though it always means hidden from normal view or perception. A thing may be a mystery—hinted at yet hidden in the present or past—then when the mystery is demonstrated and revealed it is yet referred to as “a mystery”.
The most ready example is the genre we call “mystery novels”. In our reading the story begins as a collection of facts that don’t seem to fit together in a reasonable way. By the time we arrive at the end of the narrative most, if not all, of the facts make sense and the mystery is not mysterious. However, the story is still called a mystery.
Paul uses “mystery” in a similar way when he refers to the conjoining of Jew and Gentile together “in Christ.” He also uses “mystery” in Eph. 5 when he compares Christ and the church to the marriage relationship of husband and wife (and personally I think Paul understood the Christ/church as less a mystery than husband/wife ;o) ).
It’s necessary to understand some facts before a mystery makes any sense. We can know a lot of facts about what happened between noon and three on that notorious Friday outside Jerusalem circa 30 A.D.. Knowing those facts removes some of the mystery, yet even the facts produce in us over time more not-knowings and deepening mystery. We are saved by the facts, yet the mystery draws us to the outstretched arms of senseless, wasteful, desperate, determined Love.
The facts are simple. The Love is complicated. It’s our tendency to make the mystery uncomplicated by using one simple motif in our explanation of that Love — that “we sinned, justice demands death, therefore Jesus died to pay our sin-debt.” That is true, but if that is our sole explanation and understanding, then the rich mystery of the Cross is denuded.
A well chosen single word can be a wonderful symbol. “Life” is synecdoche for all that embodies living. “The Word” is a mysterious way to speak of the logos who came to us embodied. Paul said to the Galatians, “May I never boast except in the cross of our Lord Jesus Christ, through which the world has been crucified to me, and I to the world.”