Do not you yet understand, that whatever enters in at the mouth goes into the belly, and is cast out into the draught?…
You never need educate any man into sin. As soon as ever the young crocodile has left its shell it begins to act just like its parent, and to bite at the stick which broke the shell. The serpent is scarcely born before it rears itself and begins to hiss. The young tiger may be nurtured in your parlour, but it will develop ere long the same thirst for blood as if it were in the forest. So is it with man; he sins as naturally as the young lion seeks for blood, or the young serpent stores up venom.
(C. H. Spurgeon.)
Parallel VersesKJV: Do not ye yet understand, that whatsoever entereth in at the mouth goeth into the belly, and is cast out into the draught?