Church Service in Bach's Time

We obtain better perspective on today's church services by studying church services of the past. By perspective, I mean noting differences and similarities--in other words, we can compare things. According to the Oxford Dictionaries online, to compare is to

Estimate, measure, or note the similarity or dissimilarity between

So that we can measure and note similarities and dissimilarities, I revisit the order of service in Bach's day in Leipzig. 

Thomaskirche Leipzig

It was no light matter to stay in the church for three or four hours, which was the time the services lasted. - Schweitzer 

1. The service officially begins 7:00 am.
2. The organ prelude begins.
3. A motet is sung.
4. Then comes the Introit, and after that the Kyrie. The latter is sung twice: once in German, once in Latin.
5. The Gloria is then intoned from the alter, and answered either by the choir or by the congregation. 
6. After the collect, the Epistle is read, or rather is sung in the old psalmody. 
7. Then comes a congregational hymn.
8. The Gospel is chanted by the priest, who also intones the Credo. 
9. The organist begins to preludise, keeping to the keys which the instruments need for tuning.
10. The cantata begins, which lasts on average 20 minutes. 
1. Notes: The cantata was generally shorter in winter than in summer. During winter, the interior of the church could be very cold, and parishioners became uncomfortable.  The cantor kept the cantata length closer to 20 minutes so as not to extend the service length. Also of note: the choristers maintained a coal fire.
11. The sermon begins and, according to rule, lasts one hour. Choristers of St. Thomas leave the church during the sermon, but they do not escape the sermon. They have to read one during the hour that they are not in the church.
12. Sermon is followed by a prayer and a blessing.
13. A congregational hymn leads to the second part of the service: the communion celebration. German hymns are usually sung during the communion. Organ improvisation is also played during communion. 

Further activities for Sunday:

1. At 11:45 am, there is a short service with a sermon. 
2. Vespers begin at 1:15 pm, with a motet, followed by various prayers and congregational hymns. Then comes another sermon, which is as a rule on the Epistle. After the sermon is the German Magnificat. 
3. In conclusion, the hymn "Nun Danket alle Got" is sung. 

Further notes:

1. "There was no specific Leipzig hymn-book; the congregation was supposed to know the hymns allotted to each Sunday."
2. In Bach's notes for the order of service, he calls service "divine service." 

We easily observe differences in length, format, and variety of music. Let us not forget, however, the point of comparison that diminishes the importance of all other points. It is this: the music director is Johann Sebastian Bach. At least for me, I need a few minutes of quiet thought to grasp that fact.

Source: Schweitzer, Albert. J.S. Bach, Volume One. pp 126-128. Translated by Ernest Newman. Dover Press.