Does the Holy Spirit have you? Does he have all of you, or only some parts of you? Do you grieve him? (see Eph. 4:30), or are you led by him (see Rom. 8:12-14, Gal. 5:18-24)? Do you rely on him to enable you for all those responses to Christ to which he prompts you? Do you reckon with the fact that “… your body is a temple of the Holy Spirit, who is in you, whom you have received from God? …” (1 Cor. 6:19 NIV). Do you revere his work within you and cooperate with it or obstruct it by thoughtlessness and carelessness, indiscipline and self-indulgence? Here again, the specific questions must be understood Christ-centeredly; they are all in reality ways of asking whether Christ your Savior is Lord of your life. But to ask them in relation to the Spirit, who indwells us in order to transform us and who works constantly in our hearts and minds to bring us close to Christ and keep us there and who is himself as close as can be to any foul thinking or behavior in which we allow ourselves to engage, is to give them a force and a concreteness that otherwise they might not have. In the world of projecting pictures onto screens this would be called sharpening the focus.
J.I. Packer in Keep in Step with the Spirit, p.78