Chapter 23, “The Public Announcement of a Wedding” (pp.169-170)
The custom of a public announcement of a wedding is positive. Walther considers that it allows public examination in case of reasons to refuse the marriage. It also allows the congregation to pray for the couple. Normally the announcement (publishing the banns) happens three Sundays in a row. In case of objection, the objection must be resolved before the couple may marry. Normally the banns were not published on Christmas, Easter, or Pentecost, though they could be on the second of each of those seasons.
Walther advises (p. 170) that the pastor warn against marriages between Lutherans and those who might turn the family away from the faith.