Emptiness in Mahayana Buddhism provides the context for (many) (most) (all) other meditations, teachings and discussions. Expressed as an idea, Emptiness asserts a complete contingency as the mode of existence of anything we can think of, conceptualize, perceive in any fashion or experience. If there is anything not covered by this, it too is Empty.
But this is not the basic assumption of how we go about our lives, interpreting raw stimulus or categorizing our experience. The axiom of our experience is that we really exist, there is something that exists in and of itself.
Expressed as the axiom of experience, Emptiness is Compassion. If our lived experience starts from a reflexive understanding of Emptiness, there is no my or mine containing our actions. Instead, guiding our actions is what is best for the situation.
Lojong mind training is a method used in Tibetan Buddhism to encourage a change from “I really exist” starting point for our actions, to one that sees the illusionary character of this perspective. Compassion then naturally becomes the basis for all one’s actions. It is the result and proof of this training, of this change in perspective.
Lojong training is a series of meditations based on a set of slogans. One of these is sometimes translated as “Be Grateful to Everyone”.