Honen advocated Senju-nenbutsu based on a verse in 'Sanzengi' from Zendo's "Kangyosho (Kanmuryoju-kyosho)" that says, 'Repeat the name of the Amida Buddha with all of your heart, never forget the Buddha when you are walking, staying still, sitting or sleeping, at any time, then you will have the correct actions, in compliance with the wish of the Buddha for the salvation of all living things.'
法然が専修念仏を唱道したのは、善導の『観経疏』（観無量寿経疏）「散善義」の中の、「一心に弥陀の名号を専念して、行住坐臥に、時節の久近を問はず、念々に捨てざる者は、是を正定の業と名づく、彼の仏願に順ずるが故に」という文からである。