2 Corinthians 4:5-7
For we preach not ourselves, but Christ Jesus the Lord; and ourselves your servants for Jesus' sake. For God, who commanded the light to shine out of darkness, hath shined in our hearts, to give the light of the knowledge of the glory of God in the face of Jesus Christ. But we have this treasure in earthen vessels, that the excellency of the power may be of God, and not of us.
Have you ever done service withour recognizing who sent you? Jesus is the reason for our service.
Also, He has deposited in us all that we need to do what He sent us, so we are short of nothing. There is actually no excuse for excellence. You have all that you need to do His work.