Bach: Wo soll ich fliehen hin, BWV 5

This morning I listened to Bach's Wo soll ich fliehen hin, BWV 5.  I thought I noticed something in the third movement, but I had to look up the notation and the text to make sure.

Part of the text for the third movement is "Ergieße dich reichlich du göttliche Quelle" ("Flow amply, you divine spring").  There's a leap of almost an octave (Bb to Ab, if I'm reading the notation correctly) for the first part of "Quelle" ("spring"), and a full octave (Ebs) in the bass part:

(notation found here)

That leap sort of musically represents the flowing or springing of the source.