Related:

• Train up a child in the way he should go; and when he is old he will not depart from it.
  -- Proverbs 22:6...
• As a dog returns to his vomit, so a fool returneth to his folly.
  Seest thou a man wise in his own conceit? There is more hope of a fool than of him....
• Boast not thyself of to-morrow; for thou knowest not what a day may bring forth.
  -- Old Testament -- Proverbs xxvii, 1...
• Iron sharpeneth iron; so a man sharpeneth the countenance of his friend.
  -- Old Testament -- Proverbs xxvii, 17...
• When faith is kneeling by his bed of death, And innocence is closing up his eyes, Now if thou wouldst, when all have given him over, From death to life thou might'st him yet recover.
  -- Michael Drayton (1563-1631) -- Ideas, An Allusion to the Eaglets, lxi...
• Answer a fool according to his folly. -- Old Testament -- Proverbs xxvi, 5
• There is an ancient saying, famous among men, that thou shouldst not judge fully of a man's life before he dieth, whether it should be called blest or wretched.
  -- Sophocles (496-406 BC) -- Trachiniae, 1...
• Heap coals of fire upon his head. -- Old Testament -- Proverbs xxv, 22
• Only a fool is astonished by the foolishness of mankind. -- Edward Abbey