The opening movement of the Magnificat in D Major, BWV 243, represents one of Bach’s most joyful moments. His use of three trumpets, plus oboes and flutes, even before the voices enter many bars later, adds to the festivities.
As a flutist, I adore No. 9, an intricate four-part movement for solo alto voice, two flutes and continuo. The obbligato flutes, playing in parallel thirds, add to the textural beauty and symbolism of the movement, entitled Esurientes implevit bonis (He hath filled the hungry with good things). Have a listen here.