集諸經禮懺儀 2.19

2.19

The second is cultivation without remainder: that is to say, exclusively reciting that Buddha's name, exclusively recollecting, exclusively envisioning, exclusively worshipping, and exclusively praising that Buddha and all the noble multitude, without mixing in other karmas; hence it is called cultivation without remainder. Making the end of one's life the limit, vowing never to halt midway, this is long-term cultivation.