Bodhicitta, Striving for Enlightenment

Bodhichitta is the one practice we cannot do without. Even if we have been given the precious oral instructions on realizing the nature of mind, they will not be the sufficient cause for realization if we have not learned to generate Bodhichitta. The great Dzogchen yogi Patrul Rinpoche said,
" If we have only one thing, the precious Bodhichitta is enough.
If we have nothing else, we must have the method of the precious Bodhichitta."
We should learn to develop Bodhichitta in a twofold way: through our aspirations and through our actions. Aspiration Bodhichitta is our initial wish that all sentient beings be liberated from the vast ocean of samsara's suffering. Action Bodhichitta requires that we first generate aspiration Bodhichitta, and practice the Six Paramitas as the method to establish the two benefits of 1) attaining Buddhahood oneself to 2) be of ultimate benefit to others. The way to practice aspiration and action Bodhichitta was taught by the omniscient Patrul Rinpoche, who said,
" The instructions for aspiration [Bodhichitta] are to practice the Four Immeasurables;
The instructions for action [Bodhichitta] are to practice the Paramitas."
Anyen Rinpoche, The Union of Dzogchen and Bodhichitta

Bodhicitta is like yeast that never looses potency. Anytime we add the moisture of warmth and compassion it will automatically expand. If we keep it in the freezer however, nothing happens.
Pema Chodron; The Places that Scare You

His Holiness the Dalai Lama

Bodhicitta or the altruistic aspiration to attain Enlightenment for the benefit of all sentient beings is a state of mind which cannot be cultivated or generated within one's mental continuum simply by praying for it to come into being in one's mind. Nor will it come into existence by simply developing the understanding of what that mind is. One must generate that mind within one's mind's continuum.
In order to engage in meditation with sustained effort over a period of time what is crucial is first of all to be convinced of the positive qualities of that mind, and the benefits and merits of generating such a state of mind. It is only when one has seen the qualities, merits and benefits of generating such a state of mind that one will be able to generate within oneself a genuine enthusiasm and perseverance in engaging in a meditation which would enable the individual to generate the mind.

Any sense of conceit or self-importance gets in the way of cultivating the genuine altruistic intention, and the most effective remedy against this is the cultivation of humility.
I can tell you a more recent story to illustrate this point. The great nineteenth-century Tibetan Dzokchen meditator Dza Patrul Rinpoche always maintained a demeanour of true humility. At one time, when he was giving a series of teachings to a large crowd of students, he experienced a forceful yearning for solitude. So one day he quietly left his residence and disappeared, dressed like an ordinary pilgrim and carrying a walking staff and very little else. When he reached a nomadic camp he sought shelter for a few days with one of the families. While he was staying with them, his hostess asked him to read some texts and, since he looked just like an ordinary pilgrim, in return for his food and lodging she asked him to help with the household chores, which included the disposal of the contents of her chamber pot.
One day, while he was away from the camp attending to this task, some of his well-dressed monk students came looking for him. When his hostess heard their description of him, she suddenly realised this was the same person she had asked to throw away the contents of her chamber pot. (It is said she was so embarrassed that she just ran away!) Such was the humility of this great teacher, who had many thousands of students.
...great practitioners of the altruistic intention also possess a tremendous courage grounded in real inner strength.... This combination of a total lack of conceit yet possessing great depth of courage is what is required in a true practitioner of bodhicitta, the altruistic mind of awakening.
Lighting the Way

The question arises, how to develop infinite altruism? It seems that it is possible to develop infinite altruism through wisdom and intelligence. Normally, when one talks about the need to cultivate love and compassion for others, one feels that this will be of benefit and help to others, but of no help to oneself, or irrelevant to oneself. This is a mistaken viewpoint because when you develop love and compassion for others, you are able to mentally develop profound satisfaction and courage. As a result you, the practitioner, benefit. You will have less fear, more willpower, more self-confidence. Automatically, one mentally becomes calmer.
Many Ways to Nirvana: Reflections and Advice on Right Living

Ho! Mesmerized by the sheer variety of perceptions,
which are like the illusory reflections of the moon in water,
Beings wander endlessly astray in samsara’s vicious cycle.
In order that they may find comfort and ease in the luminosity
and all-pervading space of the true nature of their minds,
I generate the immeasurable love, compassion, joy and equanimity
of the awakened mind, the heart of Bodhicitta.
Jikme Lingpa

SHANTIDEVA

What need is there to say more?
The childish work for their own benefit,
The buddhas work for the benefit of others.
Just look at the difference between them.

If I do not exchange my happiness
For the suffering of others,
I shall not attain the state of buddhahood
And even in samsara I shall have no real joy.

May I become food and drink in the aeons of famine for those poverty-stricken suffers.
May I be a doctor, medicine and nurse for all sick beings in the world until everyone is cured.
May I become never-ending wish-fulfilling treasures materialising in front of each of them as all the enjoyments they need.
May I be a guide for those who do not have a guide, a leader for those who journey, a boat for those who want to cross over, and all sorts of ships, bridges, beautiful parks for those who desire them, and light for those who need light.
And may I become beds for those who need a rest, and a servant to all who need servants.
May I also become the basic conditions for all sentient beings, such as earth or even the sky, which is indestructible.
May I always be the living conditions for all sentient beings until all sentient beings are enlightened.