In order to achieve this wisdom, first we have to make our mind malleable, workable—in the sense of being in control of our own mind. As Shantideva said, if you want to walk comfortably, there are two possible solutions. Either you can try to cover the whole ground with leather—but that would be very difficult—or you can achieve the same effect by simply wearing a pair of shoes. In the same way, it would be difficult to train and tame every single emotion that we have, or to change the world according to our desires. In fact the basis of all experience is the mind, and that’s why Buddhists stress the importance of training the mind in order to make it workable and flexible.
Yet a flexible mind is not enough. We have to understand the nature of the mind. This is very difficult to do, precisely because it involves the wisdom of realizing egolessness. We have been in samsara from beginningless time. Our habitual patterns are very strong. We are completely deluded. For this reason, it is very, very difficult for this wisdom to appear.
So what is to be done? There is only one way to obtain this wisdom—by accumulating merit. How should we accumulate this merit? According to the general vehicle of Buddhism, the method of accumulating merit is by having renunciation mind, by contemplating impermanence, by refraining from all the causes and conditions that will strengthen the ego, by engaging in all the causes and conditions that will strengthen our wisdom, by refraining from harming other beings, and so on. In the mahayana school, the merit is accumulated by having compassion for sentient beings.
To cut a long story short, if you want enlightenment you need wisdom. If you want wisdom, you must have merit. And to have merit, according to mahayana, you must have compassion and bodhichitta, the wish to establish beings in the state of freedom.
– Dzongsar Khyentse Rinpoche