Upekkhā Sambojjhanga…
When the disciple develops his concentration, he sees it also as an element in the path of the realization of the Four Noble Truths and does not attach to concentration either. He sees that there is a concentration that has the nature of impermanence. Then, his mind becomes indifferent. He thus builds an equanimity in him. He then even does not grasp that equanimity. He does not get deceived by that equanimity. He cultivates that equanimity as an element for the realization of the Four Noble Truths.