仁王般若經疏 3.159

3.159

時諸大眾阿須輪王，聞佛所說未來世中七可畏難，身毛為竪呼聲大叫而言：「願不生彼國。」時十六大國王即以國事付弟，出家修道，觀四大四色勝出相，四大四色不用識空入行相。

At that time, when the great assembly and the asura kings heard the Buddha speak of the seven terrifying calamities in future ages, their bodily hairs stood on end, and crying out in loud voices, they said: "We vow not to be born in those lands!" At that time, the sixteen great kings immediately entrusted the affairs of state to their younger brothers, renounced household life to practice the Path, contemplating the characteristics of transcendent mastery of the four great elements and the four colors, and the characteristics of meditative practices entering into the four great elements, the four colors, non-possession, consciousness, and space.