Background
In Buddhist practice, meditation is not a passive state of blank awareness, but an active, skillful framework driven by three distinct qualities of mind. While mindfulness (sati) remembers where to keep your attention and alertness (sampajāna) tracks what is happening in the present moment, ardency (ātāpī) supplies the dedicated energy to abandon unskillful thoughts and cultivate skillful ones. Together, this triad transforms simple awareness into a powerful engine for developing deep concentration and insight.
For more on this see Ṭhānissaro Bhikkhu's "The Agendas of Mindfulness."