The Washington Bach Consort. (Courtesy of Washington Bach Consort)

Led by J. Reilly Lewis, the Washington Bach Consort ushered in the holiday season Saturday at National Presbyterian Church with “Great Glad Tidings,” a program of Johann Sebastian Bach’s cantatas and a mind-blowing organ masterpiece, all geared to Christmas. From start to finish, the capacity audience loved it.

The afternoon opened with two cantatas that are worlds apart emotionally: the jubilant “Schwingt freudig euch empor,” BWV 36, and the strangely morbid “Selig ist der Mann,” BWV 57, marking the feast day of the martyr St. Stephen — according to the Lutheran belief of Bach’s day, but seemingly contrary to today’s holiday merriment. A third cantata, “Ehre sei dir, Gott, gesungen,” BWV 248, followed intermission. All three alternated sections for chorus with those for vocal and instrumental soloists.

Despite a few ensemble slips, the Consort’s chamber choir and orchestra (on period instruments) generally delivered their usual intensely focused sound and finely nuanced phrasing. Though beautifully performed with energy and conviction, “Selig ist der Man” dwelt in mournful, even outright gory imagery, peaking at mankind’s “endless suffering writhing in its own blood like a worm.”

In the concert’s second half, Lewis gave a virtuosic account of Bach’s joyful though complex Canonic Variations on the Christmas song “Vom Himmel hoch da komm ich her,” BWV 769, which dispersed the metaphorical horrors of the preceding cantata. The variations are an on-target example of Bach’s technical demands that experts say reach beyond human capabilities. Yet Lewis offered a down-to-earth explanation of music telling of “heaven’s heights.”

Violinist Andrew Fouts offered deeply expressive solos. Soprano Laura Choi Stuart, countertenor Ian Howell, tenor Robert Petillo and basses Steven Combs and Richard Giarusso were well matched, singing with powerful emotional overtones and total conviction. Soprano Robin Smith has a sweet voice but needed to project more effectively.