This is a traditional church melody arranged as a chorale (choir or choral piece) by 19th century composer Robert Schumann. The chords are made up of four individual voice parts written on the grand staff – Soprano and Alto on the treble staff, Tenor and Baritone on the bass staff.
The parts are determined by their stem directions, i.e., soprano and tenor parts have their stems pointing up, while the Alto and Bass parts have their stems pointing down. This arrangement contains extensive use of chord inversions. Listen to how smoothly the voices move between the chords.