Whatever aspects of the teachings we practice, the only point of practicing is to tame our three poisons, to tame our kleshas. Therefore, if dharma practice is effective there should be some evidence of a change in our personality, in our characters, and in our behavior. If there is no such evident change, then clearly we are wasting our time and might as well not have done it to begin with.
Whether or not this change occurs depends to a great extent on the purity of our motivation. There are many different sorts of motivations that we might have. We could have a pure motivation, a neutral motivation, or an impure motivation. Pure motivation according to the mahayana — and we are all practitioners of the mahayana since we know that all beings throughout space have countless times been our mothers — is the wish to bring all to the state of buddhahood. And this purpose, the wish to bring all beings to buddhahood, has to be with us from the moment when our butts touch the cushion. A neutral motivation is to be aimless, to practice without any specific purpose or idea why you are doing it. This is as pointless as shooting an arrow in the dark of night without aiming at any target. And an impure motivation is one that is concerned with some kind of worldly ambition, typically with one or more of the eight worldly dharmas, such as the seeking of fame, and so forth.
Now any one of these motivations may arise in our minds at any time, so we need to be vigilant and ensure that our motivation is always correct. Even among positive motivations, we must ensure that our motivation is not concerned with some sort of short-term boon, such as protection from sickness or other suffering, or any other kind of temporary benefit.
[From the White Khechari Practice Instructions, Part 1 of 3 given by Lama Tashi Topgyal in October 2011 at Kunzang Palchen Ling. Translated by Lama Yeshe Gyamtso. Complete teaching available as an MP3 download at the KPL Bookstore.]