'Discern' in the Bible

And thy bondmaid said, Let the word of my lord the king now be comfortable; for as an angel of God, so is my lord the king to discern good and bad; and Jehovah thy God will be with thee.

I am this day eighty years old: can I discern between good and bad? can thy servant taste what I eat and what I drink? can I hear any more the voice of singing men and singing women? and why should thy servant be yet a burden to my lord the king?