Quoting Edgar Cayce the "Sleeping Profit" On His Accounts Of The Akashic Records
Upon time and space is written the thoughts, the deeds, the activities of an entity – as in relationships to its environs, its hereditary influence; as directed – or judgment drawn by or according to what the entity's ideal is. Hence, as it has been oft called, the record is God's book of remembrance; and each entity, each soul – as the activities of a single day of an entity in the material world – either makes same good or bad or indifferent, depending upon the entity's application of self towards that which is the ideal manner for the use of time, opportunity and the expression of that for which each soul enters a material manifestation. The interpretation then as drawn here is with the desire and hope that, in opening this for the entity, the experience may be one of helpfulness and hopefulness.
-- Edgar Cayce Reading 1650-1
An explanation of where his soul would acquire the knowledge when he was asked to give what is known as a "Life Reading". He would reveal certain past lives which were most pertinent to the current life the person was living. It was in those specific past lives from where the karma originated, which the person chose to confront in the current incarnation.
Saint Edgar.