See if what he has to say, lines up with scripture. God's Word is the foundation upon which every true man of God will base his life, ministry and message. A real man of God doesn't seek to promote himself, but seeks to glorify Christ in everything he does or says. Just like preachers, a lot of trees may look alike from a distance, but a close inspection of the fruit hidden among the branches will reveal their differences.
Fruit is the natural product of a species which provides unmistakable identification.
Fruit of the Spirit Gal. Against such there is no law. Jesus gave us this fruit test to protect us from deceivers. It is clear that any preacher or purported man of God who exhibits the immoral works of the flesh is definitely not led by God's Spirit. It is biblical and necessary for Christians to examine the fruit of their leaders.