What is it to serve the living and true God?
The apostle says, “Whom I serve with my spirit in the gospel of His Son.” First, to serve God in spirit, not with our bodies; because we may be serving God with our bodies, and serving the devil with our souls.
There is a great deal of wickedness committed on a man’s knees: a man may be on his knees, and his heart in all manner of wickedness; a man may sit in a chapel hearing a sermon, and his heart practising all manner of abominations. That is serving God with the lips, but not with the spirit.
In other words, being made partakers of that blessed Spirit; serving him in spirit, from a feeling, believing, affectionate heart; serving in the newness of the Spirit, not in the oldness of the letter, with some manifestations of mercy and love to the soul; this is to serve in the Spirit in the gospel of his Son.”