I'm looking for a way to describe someone who is a statesman, warrior, musician and poet. Someone like King David in the Old Testament.
You might want to look here, as your question seems to be a duplicate: What is another word for 'all round' capabilities?
As a quick answer, the OED has:
Jack of all trades n. (also Jack at all trades) a man who can turn his hand to any kind (or to many kinds) of work or business; also rarely Jack of all work(s).
Polymath n. A person of great or varied learning; a person acquainted with many fields of study; an accomplished scholar.
Renaissance man n. a man who exhibits the virtues of an idealized man of the Renaissance; (now usually more generally) one with many talents or interests, esp. in the arts and humanities.
But you'd probably be better served having a look at the answers on the linked post.