Values of Punyam & Paapam

Once a foreigner interested in the philosophy of Hinduism was waiting for Darshan of Mahaperiva ( Most revered Mahaswami) at Kanchi Mutt to clarify his doubt. Shortly, he got his appointment and without wasting time, he put forth his question.

Swamiji, I understand all your concepts, value them but for one particular faith (i.e.) same soul taking various births, papa, punya being carried forward to the next births etc. Can you please make me comfortable on this aspect? Because, in all our religions, we get the reward for what we do in this birth only. (i.e.) if we are honest, God is pleased and blesses us with benefits and we are dishonest, we get punished by Him.
At this point, Periva asked him, whether he owns a car and if he could do a favour of collecting some statistical information within Kancheepuram using his vehicle. The guest readily agreed, at the same time wondering why his question was not answered spontaneously.
Please, Swamiji, go ahead, What is the service you expect me to do now?
Periva said, Please go around 10 maternity centres within Kancheepuram and collect the data of children born within the last 2 days - Child's gender, health condition, parents name, status, educational qualification, time of birth.
The man said - Fine, this is nothing, - immediately rushed in his car like Lord Muruga goes in Thiruvilayadal and within a day he was back in the matam with exact statistics in front of Mahaperiva. He went through the statistics, about 15 children were born in 10 hospitals, 8 female and 7 male infants, out of which 3 children had malnutrition defects, 2 children were the first child of highly rich parents born in luxury hospitals, while 4 were children of coolie labourers who already had few children.
Maha Periva now looked at the gentleman and started asking few questions:
Do you think any of these children have been honest / dishonest within 2 days of their birth? Probably they could not even recognize their own mother. So, they have neither earned papa or punya in this birth.
According to your concepts, all these children should be living exactly identical to each other, but not so practically, some are ill, some are healthy, some are born to rich parents, some are born to poor parents. Remember all children born in the same day, same longitude, latitude, you can't blame their horoscope which is going to be almost identical.
The gentleman was dumbfounded!
It is here the concept of previous birth erupts! All these children have taken their present birth according to their deeds (karma) and the resultant papa, punya which they have assimilated in their previous births.
Sanatana Dharma was smiling at the gentleman through Maha Periva.