Gaining some ill-gotten things are included in great sins category. Keeping the ill-gotten things is even sin, the holy Prophet (pbuh) said to the people: the one who keeps ill-gotten things and don’t take it to its owner as soon as possible, so long as he has this ill-gotten thing he is cursed by Allah Almighty. In the Quran, the meaning of curse is to be away from the Divine Mercy.
We are in dire need of Allah,s mercy and forgiveness both in this world and the Hereafter, if we are not subjected to Allah,s mercy, we are not saved from the worldly and hereafter troubles and problems.
source : erfan.ir