What most of us know about Pentecost comes from its founding story in the second chapter of the book of Acts. As described there, it is a spectacular, if somewhat chaotic, event replete with tongues of flame and the sound of rushing wind. The Holy Spirit descends on the apostles, and they begin testifying in languages other than their own. This draws a crowd of Jewish pilgrims, and now each of them is hearing about God’s “deeds of power” in his or her own language.

This is a wonder.

But let’s not go there. There is a prequel to all this excitement, and it’s found in Jesus’s Farewell Discourse, covering nearly four chapters in the Gospel of John. There we discover that Pentecost does not begin in excitement but in loneliness. And before it is miraculous testimony, it is a promise given in the dark.

Traditionally, the memoir was the province of the “great man” who embodied the achievements of his age and helped steer the course of historic events, who now, with some leisure on his hands and in need of cash, has agreed to write about it. The chief purpose of the memoir was to provide an insider’s perspective on external events, such as wars, treaties, and scientific explorations.

Sooner or later, it was a letter he would have to write. You can be abused, rejected, or taken for granted only so long before you write the proverbial “Dear John” letter. It is not a bill of divorcement King is sending to its recipients, because the White church and the Negro church have never been married. There has been the occasional pretense of love, but never the real thing. No one wanted it to end like this. Not King who tirelessly preached (and pretended) that Blacks and Whites are “brothers.” And not the recipients of his famous Letter, who, like the church bodies they represented, pretended to the same brotherhood.