Rejoicing is habituating yourself to feeling happy about all the constructive acts of the Triumphant Ones, their spiritual offspring, and all wandering beings. This is a supreme method for transforming fathomless masses of positive force into something immeasurably great.
Longchenpa
A Precious Garland for the Four Themes
source: http://www.berzinarchives.com/web/en/archives/advanced/dzogchen/basic_points/four_themed_precious_garland.html
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