Majjhima Nikaya (Coleção dos Discursos Médios) 3:11
SUJATOTasmātiha, bhikkhave, bhiyyoso mattāya vīriyaṁ ārabhatha appattassa pattiyā, anadhigatassa adhigamāya, asacchikatassa sacchikiriyāya.
So you should rouse up even more energy for attaining the unattained, achieving the unachieved, and realizing the unrealized.