Jakugen performed various Kugyo (ascetic) following the Jodo-shinko (the Pure Land faith) and Study, devoted himself to his studies of Hokke faith, and bishamonten, Vaisravana (guardian god of Buddhism) is said to have appeared before Jakugen each time to protect him ("Kokon Chomon ju" (A Collection of Tales Heard, Past and Present) and "Genko shakusho" (History of Buddhism of the Genko era)).
寂源は大原で浄土信仰・法華信仰の研鑽に励んで様々な苦行を行い、その度に毘沙門天が現れて寂源を守護したと伝えられている（『古今著聞集』・『元亨釈書』）。