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.
Trust in God's promise, not agreement with a list of propositions. Lutherans distinguish knowing about Christ from trusting him; only the second is faith in the sense that justifies.
In Doctrine — What Lutherans teach, and where it differs from neighbouring traditions.