And what fuels the arising of the awakening factor of equanimity, or, when it has arisen, fully develops it? There are things that are grounds for the awakening factor of equanimity. Frequent rational application of mind to them fuels the arising of the awakening factor of equanimity, or, when it has arisen, fully develops it.

This body is sustained by food. It depends on food to continue, and without food it doesn’t continue. In the same way, the seven awakening factors are sustained by fuel. They depend on fuel to continue, and without fuel they don’t continue.”

Linked Discourses 46.3 1. Mountains Ethics

“Mendicants, when a mendicant is accomplished in ethics, immersion, knowledge, freedom, or the knowledge and vision of freedom, even the sight of them is very helpful, I say. Even to hear them, approach them, pay homage to them, recollect them, or go forth following them is very helpful, I say. Why is that? Because after hearing the teaching of such mendicants, a mendicant will live withdrawn in both body and mind, as they recollect and think about that teaching.