Question: If a person is a very advanced seeker and develops the ability to see his past incarnations, will this actually hinder his progress? In other words, is it always harmful if you discover you were a thief or something in the past?

Sri Chinmoy: If you are meditating most sincerely in this life, your inner strength will automatically develop and you will reach the point where you will not be disturbed even if you see that you were the worst possible criminal in a previous incarnation. You know that you have come here to transform yourself, to go towards the Divine. The Lord Buddha disclosed his previous incarnations: he was a goat and many other things. But because he had realised God and had entered into the highest Truth, it was easy for him to say what he was in his previous births. To him it was immaterial if he was most ordinary in his previous incarnations.

From: Sri Chinmoy, Death and reincarnation - , Agni Press, 1972
Sourced from http://www.srichinmoylibrary.com/dr-59