I’ve been rereading Aesop’s Fables. How true they are.
The Farmer and The Snake
One winter a Farmer found a snake stiff and frozen with cold. He had compassion on it, and taking it up, placed it in his bosom. The snake was quickly revived by the warmth, and resuming its natural instinct, bit its benefactor, inflicting on him a mortal wound. “Oh,” cried the Farmer with his last breath, “I am rightly served for pitying a scoundrel.”
The greatest kindness will not bind the ungrateful.
Pastor Susan 
This is like that parable of the scorpion and frog: A frog is accosted by a scorpion who wants to cross a small stream. He promises not to sting the frog if the frog will take him to the other side. Out in the middle of the stream the frog feels the bite of the scorpions tail and exclaims, “You gave your word you wouldn’t sting me and now we’re both dead! Why would you do this?” The scorpion replied, “It’s my nature.”
It also speaks to character and casting pearls before swine. Sometimes kindness is misplaced and the time isn’t right.