On: every psalm and song in the daily prayers uses today’s English. Off: all of them use the older “thee and thou”. Until you choose, the Songs of Zechariah, Mary and Simeon use today’s English, as most churches sing them. The Lord’s Prayer and the prayers for the dying show the form most people learned.
Home/Library/Jakob Andreae, Martin Chemnitz, and others
The Formula of Concord
Free elsewhere
The settlement of the quarrels that broke out among Lutherans after Luther died: free will, good works, the third use of the law, the Supper, and how much may be conceded under pressure. In an Epitome and a Solid Declaration.