Brothers of John the Steadfast has published an Advent and Christmas devotional booklet based on the hymns of Paul Gerhardt. Here is a description of the booklet from Brothers of John the Steadfast's web page:
This Advent and Christmas devotional was written by the pastors at Our Savior Lutheran Church in Cheyenne, Wyoming. It is focused on the Advent and Christmas hymns of Paul Gerhardt as they are found in LSB and TLH. Each day goes through a stanza of the hymn, a supporting Scripture passage, a short devotional thought, and then a brief prayer. It is designed to be used as a part of your household’s normal devotional or “family altar” time.