Our experience, as described by the five aggregates, is empty in two ways. There is no self at the center of them, and every aggregate– Form, feeling, perception, formations and consciousness–is insubstantial.
"the non-doing of all harm, taking in the good, purifying the heart– This is the teaching of the awakened ones". How to cultivate taking in the good as an important foundation for practice.
There are five factors that are supported for deepening concentration, known as the jhana factors. These factors are developed in any kind of intensive meditation practice, but are particularly supportive for the development of samadhi. They also serve to counterbalance the hindrances. When the hindrances are not active, the mind and heart can be buoyant and open, allowing concentration and insight to deepen.
The practice of metta-brings five powerful benefits. It makes the heart more responsive, purifies the mind, leads to concentration, connects us to all sentient life, and brings happiness.