A person who finds such a treasure should realize that it comes from Hashem. If he does not forget that then he can think what the message from Heaven is. It is a huge opportunity to make a kiddush Hashem and help out the person who lost it and suffered the lost. If Hashem wants to give you money for you to keep, He can give it to you in a way that noone else is suffering from it.
Easy to talk when it is not you in the tormentous moment.