What is a 'Man of God' ?

A man of God-- how much that term signifies! He is a man who comes from God, is chosen and sent by Him. He is a man who walks with God, lives in His fellowship and carries the mark of His presence. He is a man who lives for God and His will, whose whole being is ruled by the glory of God, who involuntarily and unceasingly leads men to think of God. A man of God is one in whose heart and life God has taken the right place as the All in all, and who has only one desire-that God should have that place of preeminence throughout the world.
Such men of God are what the world needs.

God is seeking them so that He may fill them with Himself and send them into the world to help others to know Him. Moses was so distinctly such a man, that men naturally spoke of him with that term,--Moses, the man of God. Every believer ought to aim at being such a living witness and proof that God can live in men on earth.

This thought--of being a person so closely linked to God that others instinctively refer to him as a man of God--leads us further. It suggests the idea of the impression we make upon men and the power we can have by carrying the Holy presence of God with us.
                                                                ~Andrew Murray