Why was it that the sixth Chán patriarch Huineng made enlightenment upon hearing one line from the Diamond Sutra? Why is it that we, upon hearing the Diamond Sutra or the Heart Sutra many times over, still are not enlightened? Everybody has exactly the same potential to become enlightened or to attain Buddhahood. In this respect we are all rank. However, as far as the level of preparedness and the capacity of different individuals then then can be a great deal of difference.
Deparent from "Meditation & Tantra in Harmony - Part 38" June 2015, Melbourne Australia