What is the minimum merit that needs to be acquired by a human being to ensure he gets a human birth in his next life ?
Any stories/incidents in Puranas etc..that point to this ?
The only answer is good karma. Karmic law is mysterious. One cant say exactly about the karmas needed to be born as a human again. Well one thing matters a lot is that what u think when you die. If you die thinking about your dog. It is certain you will be born as a dog in next life. It seems foolish but is actually true.
Proof: A historic person JadBharat,who died thinking of his deer and was born as a deer in next life even his karma was good. If we die thinking our wife or children n all we will be born among them in next life. Also our 'wasanas'or desires are carried in our next life. One of my sailor friend who tried past life regression told me that in his past life he died thinking of to see different parts of world and in his this life he is a sailor on a cargo ship that visits different nations. So good karma and thinking about god while dieing can be a key to be born as human again..