I knew people who, whenever they fell ill, took that as a proof of the Divine Grace to help them to progress. They told themselves: it is a good sign, I am going to find out the cause of my illness and I shall make the necessary progress. I knew a few of this kind and they moved on magnificently. There are others, on the contrary, who, far from making use of the thing, let themselves fall flat on the ground. So much the worse for them. But the true attitude when one is ill, is to say: “There is something that is not all right; I am going to see what it is.”
Ref: Questions and Answers 1953