Afterward Jesus found him in the temple, and said to him, "Behold, you are made well. Sin no more, so that nothing worse happens to you."
Lest a worse thing befall thee ...  What could be worse than being an invalid for thirty-eight years?  The fate of unbelievers is worse.  Also, there is a temporal application as well; because there is no condition of human wretchedness so bad that further sin might not aggravate and increase it.