Colossians 3:17 (NASB) And whatever you do in word or deed, do all in the name of the Lord Jesus, giving thanks through Him to God the Father.

 

Note: "In the name of the Lord Jesus" is the same as saying by His authority (as given in the word of God). Compare:

Matthew 28:18-20 (NASB) 18 And Jesus came up and spoke to them, saying, "All authority has been given to Me in heaven and on earth. 19 "Go therefore and make disciples of all the nations, baptizing them in the name of the Father and the Son and the Holy Spirit, 20 teaching them to observe all that I commanded you; and lo, I am with you always, even to the end of the age. "