Even if a person becomes ill or incurs a financial loss due to natural causes, he should still have complete belief that it is because of his sins. That is why Chazal said, “If a person sees that he is suffering, he should check his deeds”. I have also heard of a great man, who feared Hashem and kept away from all bad things, whose approach was that whenever he incurred a business loss or misplaced something, as soon as he returned from the marketplace he would say the Viduy and cry and say that it was his sins which caused him this loss. Nowadays, because of our sins, no-one takes any notice. Instead, they think what could be the natural cause for the loss: this illness came about for this reason, this loss came about for that reason etc. and they do not even consider thinking about their deeds and repenting.
The commentaries have already said that the word “Hateva”, meaning nature, has the same gimatria (numerical value) as the word “Elokim”, meaning G-d. This is to show that all that occurs is with the supervision of Hashem. How good it would be if when a person sees that he is suffering, that he would properly accept upon himself to refrain from a bad thing which he had been used to do, and to commence something good to which he had not been used, and by doing this he will achieve the effect of having brought an offering to Hashem.