Musar for Berakhot 9:9

And even if he sees that there are some people who entirely neglect their Torah studies and yet succeed in business, let him reflect always upon their affairs, and he will see that very often they run into adversities, such as being set upon by brigands and the like and losing much of their money thereby. And this, because of their having amassed money which was not theirs [viz. (Jeremiah 17:11): "One who makes money, but not by just (means) — in the half of his days he shall lose it"], or in a time that was not theirs, but which should have been set aside for Torah study and Divine service. As we find in Avoth d'R. Nathan (29:2): "All who nullify words of Torah are assigned 'nullifiers' correspondingly (who come and nullify what they have labored in until now), such as lions, wolves, leopards, tigers and snakes. And brigands and robbers come and belabor him and exact payment of him. As it is written (Psalms 58:12): "But there is a G-d who judges the land," measure for measure. Because he nullifies Torah and toils for wealth, he is assigned "nullifiers," who nullify what he has toiled in until now. For even if the lions and the wolves do not kill him, they nevertheless cause him monetary loss, so that he must flee them and abandon his possessions or heal himself from their wounds. And many times great suffering and rare illnesses come to him from Heaven until, in the end, he spends [on doctors] that money that he did not want to give for charity. As they have said: "A house that is not open to the poor is open to the doctor." And this, too, sometimes results from the neglect of Torah study. As Chazal have said (Berachoth 5a): "If a man sees afflictions besetting him, let him examine his deeds. If he did examine [them] and did not find [anything to attribute them to], let him attribute [them] to neglect of Torah study."