Literal meaning, alluding to the variety in qualities of humankind.

From the Bible, Matthew 22 (King James Version):

22:11 And when the king came in to see the guests, he saw there a man which had not on a wedding garment:
22:12 And he saith unto him, Friend, how camest thou in hither not having a wedding garment? And he was speechless.
22:13 Then said the king to the servants, Bind him hand and foot, and take him away, and cast him into outer darkness, there shall be weeping and gnashing of teeth.
22:14 For many are called, but few are chosen.