Gottes Sohn ist kommen

"Once He came in blessing" or literally God's Son will or is, coming.
This little gem is from Helmut Walcha's 20 Choralvorspiele - Volume II # 5 published by Verlag/ C. F. Peters

Walcha was blinded at age 19 due to a smalllpox vaccination. He entered into the Leipzig Acadamy and became assistant cantor under Günther Ramin at the Thomaskirche. In 1929 he left for Frankfurt am Main after accepting a position at the Friedenskirche eventually ending up at die Dreiköningskirche also in Frankfurt. He was able to memorize the works of JS Bach only after one hearing of the work. He also recorded the entirety of Bach's organ works twice - once in mono and a second time in stereo.
He remains a huge mystery because only a few organists have been able to capture the essence of his organ works. Many play mechanically perfect but miss the complex play of harmonies within the counterpoint. He reminds me of Johannes Brahms ~ often interweaving the choral melody in the inner voices that can only be brought about by proper articulation and attention to registration.

I have not yet been able to crack the code of Walcha, but, this piece is fairly straight forward with the ostinato left hand, under the Trompete with an un-embellished presentation of the choral melody.