Today is the Feast of Pentecost (or Whitsun), which commemorates the occasion when the Holy Spirit descended on the Apostles after the Resurrection and the Ascension. Many Christians celebrate Pentecost as the “Birthday of the Church”, and denominations that closely observe the liturgical calendar consider it a holy day second only to Easter.
In honor of the occasion, below is a video of the cantata “Erschallet, ihr Lieder, erklinget, ihr Saiten!” (“Ring out, you songs; sound, you strings!”, BWV 172) by Johann Sebastian Bach, as performed by the Monteverdi Choir, conducted by John Eliot Gardiner.
See the YouTube page for the full libretto (in German).
Hat tip: ritamalik.