How does the sound of Buddha-recollection that spontaneously arises in the mind come into being? Who is recollecting the Buddha?

The recollection of the Buddha's name that arises involuntarily is all initiated by the manas; it is the manas that is reciting the Buddha's name. At first, the mind consciousness cannot perceive it, and once it does become aware of it, it cannot control it and has no choice but to follow along and listen to the sound of the Buddha's name. Being conscious is the mind consciousness's own awareness; being involuntary is not the mind consciousness's own awareness, but the manas's awareness and the manas's activity. This kind of buddha-recollection samādhi is a state of meditative concentration, and this concentration is relatively firm. Relying on this samādhi state, if one then engages in contemplative practice (vipaśyanā-caryā) of the four foundations of mindfulness, the mind is also pure, and contemplative practice becomes easy.

When the sound of reciting the Buddha's name arises involuntarily, continuing unbroken and lingering in the mind and in the brain, this is the samādhi of buddha-recollection. All kinds of samādhi arise from the manas. Why can the manas give rise to samādhi? For those whose buddha-recollection practice is not yet proficient, the samādhi of buddha-recollection will not appear; for those whose contemplative practice in various respects is insufficient, samādhi states will not appear either. What is meant by proficient practice is that, through long-term persistence in one kind of cultivation, the manas has been successfully permeated; once the manas has been cultivated through permeation, it will recite the Buddha's name and engage in contemplative practice automatically and spontaneously, and then all kinds of samādhi will appear. The arising of the various samādhis is not decided by the mind consciousness and is not controlled by the mind consciousness; the mind consciousness can only passively accept and passively merge into the samādhi state, experiencing the samādhi and the feelings of body and mind within it.