He who covets what belongs to another deservedly loses his own.

Related:

• Every one is bound to bear patiently the results of his own example.
  Phaedrus (c. 8 A.D.) -- Book i, Fable 26,...
• I knew that before you were born." Let him who would instruct a wiser man consider this as said to himself.
  Phaedrus (c. 8 A.D.) -- Book v, Fable 9,...
• Whoever has even once become notorious by base fraud,
  even if he speaks the truth, gains no belief. -- Phaedrus...
• No one returns with good-will to the place which has done him a mischief.
  Phaedrus (c. 8 A.D.) -- Book i, Fable 18,...
• Jupiter has loaded us with a couple of wallets: the one,
  filled with our own vices, he has placed at our backs...
• Things are not always what they seem. -- Phaedrus (c.
  8 A.D.) -- Book iv, Fable 2,...
• That it is unwise to be heedless ourselves while we are giving advice to others,
  I will show in a few lines. -- Phaedrus (c. 8 A.D...
• Submit to the present evil, lest a greater one befall you.
  Phaedrus (c. 8 A.D.) -- Book i, Fable 2,...
• A mountain was in labour, sending forth dreadful groans,
  and there was in the region the highest expectation...