Voluntary devotion and living in the Holy Spirit should be seen on Sundays/Sabbaths. 

Ezekiel 46:5

“…and the grain offering shall be one ephah for a ram, and the grain offering for the lambs, the gift of his hand, as well as a hin of oil with every ephah.” Ezekiel 46:5

The grain offering represents a voluntary devotion to serve God. The oil represents the Holy Spirit, who is given through Jesus Christ, as Paul asked, “Did you receive the Holy Spirit when you believed?” So they said to him, “We have not so much as heard whether there is a Holy Spirit.” And he said to them, “Into what then were you baptized?” So they said, “Into John’s baptism.” Acts 19:2-3 John said this, “I indeed baptize you with water unto repentance, but He who is coming after me is mightier than I, whose sandals I am not worthy to carry. He will baptize you with the Holy Spirit and fire.” Matthew 3:11

The ministers of the churches are to give themselves to the will of God from a voluntary devotion to Him through Jesus Christ in the presence of the Holy Spirit.