“What is the mind? The mind isn’t ‘is’ anything” (Ajaan Chah, speaking about Buddha Nature).
“Spiritual seekers still exploring the different contemplative traditions commonly assume that the highest spiritual teaching must be one which posits a metaphysical unity as the philosophical foundation and final goal of the quest for enlightenment. Taking this assumption to be axiomatic, they may then conclude that the Pali Buddhist teaching, with its insistence on the sober assessment of dualities, is deficient or provisional, requiring fulfillment by a nondualistic realization. For those of such a bent, the dissolution of dualities in a final unity will always appear more profound and complete. … The Buddha’s Dhamma does not point us towards an all-embracing absolute in which the tensions of daily existence dissolve in metaphysical oneness or inscrutable emptiness. It points us, rather, towards actuality as the final sphere of comprehension, towards things as they really are (yathabhuta)” (Bhikkhu Bodhi, “Dhamma and Non-duality”).
“Loneliness is better than [the] friendship of a fool” (P. Lal’s translation of Dhammapada, 61).
“…don’t go by reports, by legends, by traditions, by scripture, by logical conjecture, by inference, by analogies, by agreement through pondering views, by probability, or by the thought, ‘This contemplative is our teacher.’ When you know for yourselves that, ‘These qualities are skillful; these qualities are blameless; these qualities are praised by the wise; these qualities, when adopted & carried out, lead to welfare & to happiness’ — then you should enter & remain in them” (AN 3.65).
“Cittaṃ … adantaṃ mahato anatthāya saṃvattatīti” (AN 1.21-40). My translation from Pali: “A mind … untamed to great pointlessness leads.”