Bodhicitta is the wish to attain enlightenment for the sake of all suffering sentient beings.

The purpose of your life is to bring happiness - including the happiness of this life - to other sentient beings; to do whatever you can for others every day, even if it’s small – giving a smile or a few kind words to make someone happy, to release someone from tension, depression or unhappiness in everyday life, offering others whatever great or small happiness, comfort or benefit you can; taking every opportunity to bring the happiness of this life to others – is one aspect of the purpose of living for the happiness of others.  More important, however, is to bring others both the happiness of future lives in samsara and, eventually, the long-term, ultimate happiness of complete liberation from samsara, total liberation from all suffering and its cause.

And finally, even more important than that, the greatest purpose for living is to bring numberless other sentient beings, or even just one sentient being, to the peerless happiness of full enlightenment – the total cessation of all mistakes of the mind and the complete accumulation of perfect qualities; to bring one sentient being to full enlightenment or, similarly, numberless sentient beings.

We need to think very broadly.  Benefiting all other sentient beings is the meaning of our life.  There is no way to do this work of freeing others from all suffering and bringing them to full enlightenment perfectly, without the slightest mistake, other than by first becoming fully enlightened yourself.  Your own mind needs to become omniscient – knowing directly, being able to read all sentient beings’ mind, knowing all sentient beings’ different levels of mind, their individual karmas and all the various methods that suit them, that will bring them from happiness to happiness, to the peerless happiness of enlightenment.  First you must achieve full enlightenment yourself.  To achieve full enlightenment, you need to actualise the steps of the path that lead to that goal.

(Source : Teachings from the Vajrasattva Retreat, Lama Zopa Rinpoche)