Quotes from the Buddha Treasury Sutra,

Vol. 2 

“Śāriputra, this dharma of bearing the Buddha in mind cuts off the path of language; it is beyond all thoughts and in the practice of this dharma no thought can be apprehended, such is called bearing the Buddha in mind.

“Śāriputra, all thoughts are characterized by quiescence and cessation; to be in accord with such a dharma is called the cultivation of bearing the Buddha in mind. One should not bear the Buddha in mind relying on any form. Why is that? Thinking of forms leads to the apprehension of appearance; desiring specific qualities breeds discernment. The notion of bearing the Buddha in mind is that which is without shape, appearance, conditions, or properties. Hence one should know: the true way of bearing the Buddha in mind is without differentiation, apprehension, and abandonment.

“Bearing the Buddha in mind denotes the shattering of investigation and analysis toward everything good or ill; it is without investigation or analysis, and is thoughtless and quiescent. Why is that? One should not employ thought and examination to be mindful of Buddha. The absence of investigation and analysis is called the pure way of bearing the Buddha in mind.

“You should not attach to even the slightest thoughts when you bear the Buddha in mind, nor should you develop conceptual proliferation or differentiation. Why is that? All dharmas are empty of an inherent nature; hence, you should not be mindful of any kind of sign. The notion of signlessness is the true way of being mindful of Buddha.”

《佛藏經》卷中

「舍利弗，是念佛法、斷語言道，過出諸念，不可得念，是名念佛。

舍利弗，一切諸念皆寂滅相，隨順是法，此則名為修習念佛。」

「不可以色念佛。何以故？念色取相、貪味為識。無形無色，無緣無性，是名念佛。是故當知：無有分別，無取無捨，是真念佛。」

「念佛名為破善不善一切覺觀，無覺無觀、寂然無相，名為念佛。何以故？不應以覺觀憶念諸佛。無覺無觀名為清淨念佛。」

「汝念佛時莫取小相，莫生戲論，莫有分別。何以故？是法皆空，無有體性，不可念一相。所謂無相，是名真實念佛。」