'Burden' in the Bible

and David saith to him, 'If thou hast passed on with me then thou hast been on me for a burden,

A son of eighty years I am to-day; do I know between good and evil? doth thy servant taste that which I am eating, and that which I drink? do I hearken any more to the voice of singers and songstresses? and why is thy servant any more for a burden unto my lord the king?