Sri Aurobindo translates Shwetashwatara Upanishad, Chapter Six, Verses 22-23: “This is the great secret of the Vedanta which was declared in a former time, not on hearts untranquilled to be squandered nor men sonless nor on one who hath no disciples. (Or, Thou shalt not bestow it on a soul untranquillized, nor on the sonless man nor on one who hath no disciple.) But whosoever hath supreme love and adoration for the Lord and as for the Lord, so likewise for the Master, to that Mighty Soul these great matters when they are told become clear of themselves, yea, to the Great Soul of him they are manifest.”
The teachings are to be given to those who are prepared inwardly to benefit from them. Planting a seed in rocky ground is not going to be fruitful. The realized soul who understands, recognizes that without this inner preparation the effort is useless, and it is best not to disturb the balance and focus of those who are still attached to the outer life and its fruits. At the same time, the spiritual teachings can lead to imbalance if they are taken up by those who do not have the experience and understanding of the outer life of the world, those “sonless” or “without disciple”.
In the Christian tradition, Jesus is credited is stating that one should not “throw pearls before swine”, which was his colorful way of describing that the teachings he was propagating should not be placed before “hearts untranqillized”, that is, people who simply were not ready to hear and respond to the teachings.
In the Bhagavad Gita, Sri Krishna makes it clear that it is better for a man to follow an imperfect faith that is suited to his stage of evolutionary growth than to try to follow the faith of another that is not suited to him. He admonishes not to disturb the faith of an individual unless that individual is ready, able and receptive to taking up a new growth or direction.
The spiritual truths of Oneness, of harmony, of peace, and the experience of infinity, eternity and the sense of timeless presence are covered over by the disturbed energies of desire, attachment and acquisition. The quiet mind and heart can open with a sense of receptivity to a different order of truth and experience that brings forth the possibility of knowledge by identity.
The Upanishads recognize the need for a rise in Sattwa to counter either the darkness and sloth of Tamas or the hectic, disturbed rush of Rajas, in order to achieve the proper standpoint for spiritual experience. Sattwa brings with it a calm mind and a heart that is open with love and devotion.
Swami Vivekananda in his lectures on Raja Yoga, describes the process of attainment as needing the quieting of the mind-stuff, the chitta, so that the radiance of the Truth may reflect in the still depths of the being. This is the foundation of the experience of Samadhi.
Spirituality is not a belief. It is not philosophy, nor religion. It is the direct experience of the Truth of existence. The preparation of the being provides the basis for the Grace to act.
Sri Aurobindo, The Upanishads, Shwetashwatara Upanishad, pp.369-384