What does it mean that Christ is the Head of the Body and we function as the Body?
Christ as Head means He occupies the heavenly position of authority over His Body, while believers function as His Body on earth. As the Body, we move, breathe, eat, and live only because of Him. All things were created by Him and for Him, so His headship is both positional and life-sustaining.
Les explains that Christ, in His position in the heavenlies, is the Head, and we are functioning as the Body. He illustrates this by saying that we move as Paul told the Athenians in Acts: everything we do—breathe, eat, move—is because of Him. The surrounding context stresses that all things in heaven and earth, visible and invisible, thrones, were created by Him and for Him. This headship is also tied to His work of the cross, where the handwriting of ordinances against us was blotted out, principalities and powers were spoiled, and the Law’s shadows—meat, drink, holy days, new moons, sabbaths—were nailed to His cross.
And he is the head of the body, the church: who is the beginning, the firstborn from the dead; that in all things he might have the preeminence.