Are the Four Dhyānas and Eight Samādhis Cultivated by Non-Buddhists of Any Use?

Regardless of who one is, if one has cultivated the four dhyānas and eight samādhis, one can effectively subdue afflictions and innate afflictive obstructions (kleśāvaraṇa), and the obstacles to seeing the Way are greatly reduced. More than half of the thirty-seven aids to the Way will already have been cultivated; what is lacking is only the right knowledge and view needed for seeing the Way. If one's roots of goodness and merit are complete, and upon encountering the right knowledge and view one can believe and accept it without doubt, then wisdom will no longer be obstructed, and one may see the Way immediately. During the Buddha's time, many non-Buddhists, upon hearing the Buddha preach the Dharma, attained purity of the Dharma eye on the spot and became non-returners (Anāgāmin) or arhats, and some became stream-enterers (Srotaāpanna) or once-returners (Sakṛdāgāmin).

Wherein lies the merit of meditative concentration? It lies in the ability to subdue the manas's scatteredness and grasping, and the six consciousnesses will thereby also be subdued, no longer discriminating and fabricating in all directions. In this way the mind can at any time be concentrated on a single object, with strong power of deliberation (manana), and wisdom can be developed. If one has fully attained the four dhyānas and eight samādhis shared with non-Buddhists, and then contemplates the Buddha's Dharma, realization and enlightenment become much easier. Therefore, samādhi is one of the necessary and indispensable conditions for realizing all dharmas, and the most important direct condition.

Wisdom is born in stillness and in utmost stillness. When the mind settles down, it becomes pure; purity gives rise to wisdom, whereas turbid water disturbs the will and harms the mind. If one hopes to attain the fruits and see the true mind without cultivating meditative concentration, that is absolutely impossible; what one obtains is a fruit like foam, without practical value, which will burst after being beheld for a while.