First of all, if you lack the accumulation of merit, you will not meet with the master who possesses the oral instructions. If you lack the karmic continuity of former training, you will not understand the teachings. If you lack the special faith and devotion, you will fail to perceive the virtues of the master. If you lack vows, discipline and samayas, you will violate the root of Dharma practice. If you are not guided by the oral instructions, you will not know how to meditate. If you lack diligence and perseverance, you will not enter the pathway of practice and your virtue will stray into laziness. If your mind does not sincerely turn away from samsaric pursuits, you will not reach perfection in Dharma practice. If all these factors coincide, there will be success in Dharma practice. The accomplishment of unexcelled enlightenment depends on the coincidence of many causes and conditions, so be diligent! In short, in order to abandon what should be abandoned and accomplish what should be accomplished do not leave your body, speech and mind in ordinariness but exert yourself and the result will be excellent. Keep that in mind!

-- Padmasambhava, Guru Rinpoche