At the very heart of that bodhicitta is the understanding of universal sameness: just as you wish to be happy, others wish to be happy; just as you wish not to suffer, others wish not to suffer. Outside of superficial differences, all sentient beings, from the smallest insect to human beings, are completely identical in these wishes.
You have to do a lot of prayers for that very point of universal sameness to dawn in your heart. We want our understanding to be equally matched by the dawning of this sameness in our hearts. When it does come to reside in your heart, it forces you to act almost instinctively to treat others as you wish to be treated, and to not harm anyone as you wish not to be harmed. When this feeling of sameness is there in your heart, you can’t act otherwise but unselfishly and without solicitation for the good of others. A bodhisattva is defined by acting for others’ benefit without solicitation, by an unsolicited altruism.
Dzigar Kongtrul Rinpoche