Bach's BWV 443, 'Beschränkt, ihr Weisen dieser Welt' (Limited, you wise ones of this world), is a chorale prelude for organ. It features an intricate contrapuntal setting of the hymn melody.
Maintaining clarity in the fugal entries and developing a rich, resonant tone is key.
Beschränkt, ihr Weisen dieser Welt (BWV 443) is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
Beschränkt, ihr Weisen dieser Welt (BWV 443) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.