What does it mean to rely on wisdom rather than consciousness?

When the Buddha was about to enter parinirvāṇa, He instructed His disciples that in their study and practice of the Buddhadharma, they must strictly follow the four reliances and four non-reliances: rely on the Dharma, not on persons; rely on wisdom, not on consciousness; rely on the meaning, not on the words; rely on the definitive meaning, not on the non-definitive meaning. Although there are only these four principles, they are extremely difficult to practice, and the vast majority of people cannot accomplish them.

Among them, relying on wisdom rather than on consciousness is not something that ordinary people or ordinary bodhisattvas can achieve. First of all, this wisdom is not something that ordinary people can possess in full; this wisdom is transformed from the consciousness of ordinary beings and from the consciousness of bodhisattvas at the stage of virtuous ones before the bhūmis who have seen the Path. It is the wisdom that arises after the transformation of consciousness into wisdom — the wonderful observant wisdom (pratyavekṣaṇā-jñāna) of the mind consciousness and the wisdom of equality (samatā-jñāna) of the manas. It is the wisdom of the seed-wisdom of Consciousness-only, the profound great wisdom possessed by bodhisattvas at and above the bhūmis. The Buddha warned sentient beings that their minds are not to be believed — only after attaining the fruit of arhatship may one trust one's own mind. At the time of His parinirvāṇa, He further instructed that one must rely on the Consciousness-only seed-wisdom of bodhisattvas at and above the bhūmis, relying on the wonderful observant wisdom and the wisdom of equality. Viewed this way, the World-Honored One's two instructions echo and correspond to each other, consistent from beginning to end, encompassing the entire study and practice of both the Mahāyāna and Hīnayāna. Why did the World-Honored One emphasize this so strongly and demand this so strictly of His disciples? Because those who have attained the fruit of arhatship have exhausted their afflictions and exhausted the ignorance of one thought-moment; the wisdom of liberation has manifested, and their wisdom is free of obstruction. This is equivalent to the views and concepts of the Hīnayāna path of liberation, and only then are they free from errors and omissions, and only then can one rely on their liberating insight. As for bodhisattvas at and above the bhūmis who have completed the transformation of consciousness into wisdom, they have also eliminated the obstruction of afflictions, with only very subtle grasping at self not yet exhausted; they possess the profound wonderful observant wisdom and wisdom of equality, their Mahāyāna and Hīnayāna wisdom being extremely deep and sharp, their insight thoroughly penetrating — only their views on all Buddhadharma can be relied upon. As for everyone else, the Buddha said: take utmost heed not to trust your own mind — because they have the obstruction of afflictions and lack wisdom, their errors and omissions are relatively serious.