Handel wrote numerous oratorios (essentially unstaged operas based on Biblical stories and themes), many of which are still very popular today. While his most well-known is probably Messiah, another oratorio that has seen a good amount of performance is Samson. From that oratorio, the aria Let The Bright Seraphim arises. It is also sung in recital as a stand-alone piece, and for our purposes here, is easily adapted as an instrumental piece for weddings.
The tempo is sprightly and joyful, and works for organ or string quartet very well. It can also be played as a piano solo or as a violin/piano, trumpet/organ or trumpet/piano duet.
By the way, if you look at the lyrics below and think "what a short song!", think again. In true Handel fashion, he constructs an entire multi-page aria with a minimum of text and a maximum of text repetition!
Let the bright Seraphim in burning row,
Their loud uplifted Angel-trumpets blow:
Let the Cherubic host, in tuneful choirs,
Touch their immortal harps with golden wires.