Ein Herz, das seinen Jesum lebend weiß (A heart that knows its Jesus is living), [1] BWV 134, is a church cantata for Easter by Johann Sebastian Bach.

On Easter Sunday of 1724, he had performed Christ lag in Todes Banden, BWV 4, from his time in Mühlhausen.

He kept the final chorus as a conclusion, unlike Erfreut euch, ihr Herzen, where it had been moved to the opening and replaced by a chorale.

Bach revised the whole cantata, writing a new score with detailed improvements, possibly first performed on 12 April 1735.

[5] The cantata in six movements is scored for alto and tenor soloists, a four-part choir, two oboes, two violins, viola, and basso continuo.