It is definitely based on teachings found in classical Jewish legal and ethical sources.
Having said that I would like to think that if I were in his position of finding such a large amount of money that I would act like he did and return it with the same clarity of honesty and integrity as he expressed: “Right away my wife and I sort of you know looked at each other and said, ‘We can't keep this money’.”
In Jewish law, there is a branch of rules regarding “Lost and Found”. Many various factors are involved and the rules are often complex. Sometimes, one needs to make a special effort to find the owner and is not allowed to keep the object for himself. At other times, depending on the circumstances of how one found the object and the nature of the object, one is allowed to keep it for himself.
In a case such as the one that occurred in Connecticut, the Rabbi acted in a praiseworthy and ethical manner, one that is codified in Jewish Law (C.M 266). Returning the money in this case, despite there being legal factors to perhaps keep the findings, was definitely the right thing to do. It was in accordance with a very important Jewish principle of “Kiddush Hashem” – lit. “sanctifying the name of God”. It shows the holiness of the Jewish People, who are taught to be trustworthy, honest and righteous.