If we want Enlightenment, then we need to develop compassion, Bodhichitta and a proper understanding of Voidness.’ The primary cause of Buddhahood is Bodhichitta, for which we need to develop proper compassion. To develop Bodhichitta on a sound basis, it has to be preceded by recognising all sentient beings as having been our mothers. Then, thinking of their kindness, of all beings’ kindness, we engage in practices to repay this. Then comes developing genuine love and compassion, and the pure dedication of working for the benefit of all sentient beings. The root cause of developing actual Bodhichitta is compassion. The nature of compassion is to want all sentient beings to be separated from their sufferings. To develop compassion towards sentient beings, we need a vast understanding of the suffering that sentient beings have to experience. To have a feeling for that, we have to clearly see what our own position is, here in samsara. To develop renunciation of suffering in general, we need to see that there is no ultimate happiness even in the Indra or Brahma heavens - the highest of the deva realms - and to recognise that, we need to see the suffering nature; that there is no happiness in this very life. To work hard at accumulating negative actions for the happiness of this life leads only to countless hellish rebirths, so you have to see that there is no point in such an accumulation. Since there is a very real danger of falling to one of the three lower realms, we need a means of protection, which is Refuge in the Three Gems. So, develop the proper Mahayana attitude and listen to this teaching in order to develop Bodhichitta, to attain Enlightenment for the benefit of all sentient beings.

-- Nāgārjuna