Q. What is the chief end of man?
By "chief end" we refer to the highest goal or purpose. When we speak of "man," of course, we speak of human beings generally.
A. Man's chief end is to glorify God, and to enjoy him forever.
Two answers are provided, one objective and one subjective. Objectively man's principle goal is to glorify God. Man will do this. Man will achieve this end, whether man so intends and designs, or not. God sees to it that He himself is glorified. This is the same chief end of all of creation: to glorify God.
But there is something that sets man apart from the lower creation, and that is the subjective goal of man: namely to enjoy God forever. That is the best end for a man, to enjoy God forever. Unlike the objective purpose of man, this subjective purpose is not achieved by all men. No all men will enjoy God forever, even though all will glorify God one way or another.
Before we leave this question, we should note that subjectively as well as objectively, man ought first to seek the glorify of God, even without regard to the end of enjoying God forever. In other words, man ought consciously to seek the glory of God. The glory of God should be behind what we do.
Keeping the glory of God in mind as our principle objective (our "mission statement" to borrow from modern management terminology) can help steer us away from sin. Before we act we ought to think whether our action will glorify God. It's easy to say (or to write) such instructions, but it is much harder to live them.
God is Great, let us worship Him, forever and ever,