Gerhard and Walther

Consequently, hold to the fact that only those works and labors are forbidden on the Sabbath which are undertaken out of greed or carelessness, or out of disregard for the office of the ministry. These hinder the conducting of the worship service or keep others away from it.—Johann Gerhard, Schola Pietatis III:405.

It is impossible to be a Christian and not be thankful to God.—C. F. W. Walther, God Grant It!, p. 703.