Cantata no. 66: Erfreut euch, ihn Herzen, BWV.66

Erfreut euch, ihr Herzen (Rejoice, you hearts), BWV 66.2, BWV 66, is a church cantata for Easter by Johann Sebastian Bach. He composed it for the Second Day of Easter in Leipzig and first performed it on 10 April 1724. He based it on his congratulatory cantata Der Himmel dacht auf Anhalts Ruhm und Glück, BWV 66.1, first performed in Köthen on 10 December 1718.

The prescribed readings for the second of three Easter feast days included the narration of the Road to Emmaus. The cantata was Bach's first composition for Easter as Thomaskantor in Leipzig. He derived it from his earlier Serenata, which had a similar celebratory mood. An unknown librettist solved the problem that Bach's congratulatory cantata was a dialogue of tenor and alto by retaining a dialogue in three movements, assigned to Hope and Fear. They represent different attitudes to the news of the Resurrection of Jesus, which may be found in the two disciples, discussing the events on their walk, but also within the listener of the cantata.