Ich dank dir schon durch deinen Sohn BuxWV 195

This chorale deals with the subject of faith, trust, and forgiveness.

Ich dank dir schon durch deinen Sohn,
o Gott, für deine Güte,
dass du mich heut in dieser Nacht
so gnädig hast behütet.

I thank you through your son,
Oh God for your goodness,
that you protected me
so mercifully in this night."

It consists of 8 verses in total.
The author is Michael Praetorius.

It is not known, if Buxtehude had a certain verse in mind when composing this Fantasia, or that he more tried to capture the meaning of the whole hymn.

This Fantasia was written in Stylus Antiqua; something 17th and 18th century composers sometimes did to honour the ways of the past and to aquire the necessary skills to compose that way.

Although the chorale is quite short consisting of only four phrases, Buxtehude's setting is somewhat long at just over 150 measures.

For each phrase of the chorale Buxtehude makes a fugue using the music from the chorale as the subject for imitation.
This type of composition is often known a chorale ricercar.
The ricercar was an imitative genre related to the fugue.
Ricercari were often multisectional with each section using a different subject for imitation.

"Ich dank dir schon durch deinen Sohn" behaves exactly like a four-section ricercar.