The only things I can find are in relation to Lent:
"From the perspective of The Lutheran Church—Missouri Synod, "giving something up for Lent" is entirely a matter of Christian freedom. It would be wrong, from our perspective, for the church to make some sort of "law" requiring its members to "give something up for Lent," since the Scriptures themselves do not require this.
If, on the other hand, a Christian wants to give something up for Lent as a way of remembering and personalizing the great sacrifice that Christ made on the cross for our sins, then that Christian is certainly free to do so — as long as he or she does not "judge" or "look down on" other Christians who do not choose to do this."