The flame represents the great final effort to achieve Awakening (bodhi). To the power of śamatha (samādhi, sati, pīti, passadhi, upekkhā) he has added energy (viriya) and investigation (dhamma vicaya), thus completing the Seven Factors of Awakening. The sword represents the Insight wisdom (vipassanā) obtained through investigation and is used to cut through ignorance and mental defilements.
