His disciple Huang Po summarized the teaching of Hui-neng as follows:
Both the Buddhas and all sentient beings are of one Mind (universal consciousness or no-mind) only, and there are no other objects. This Mind has no beginning, was never born, and will never pass away; it is neither blue nor yellow; it has no shape, no form; it does not belong to the category of being and non-being; … it transcends all measurements, names, marks of identification, and forms of antithesis. ….. Stop your thoughts, forget your hankerings, and the Buddha reveals himself right before your eyes.
The teachings of Hui-neng handed down in this sutra begin with his autobiography, which contains the essence of his teachings in a symbolic story. He describes himself as an uneducated lumberjack who heard a monk recite the Diamond Sutra, one of the important scriptures of the Mahayana and Zen Buddhist tradition, in a market place. The Diamond Sutra derives its name from "the teaching that, like a diamond, cuts through all dualistic thoughts and attachment to objects and brings man to the shore of enlightenment". While listening, Hui-neng recognized the essence of this teaching and he wanted to learn more about it. He asked the monk where he could learn more about it, and the monk referred him to the 5th Patriarch, Hui-jen. So Hui-neng went to his monastery.
A southern barbarian becomes a Buddha
Upon arrival, the patriarch asked him where he came from and what he wanted. Hui-neng replied that he was a lumberjack from the south and that he came to obtain Buddhahood. Hui-jen asked, "As an illiterate southern barbarian, how can you become a Buddha?" Hui-neng replied: "Although there are north and south men, north and south make no difference to their Buddha nature. Physically, a barbarian is different from Your Holiness, but there is no difference in their Buddha-nature.”
This answer surprised the patriarch and his disciples because it showed that Hui-neng had deep wisdom even without having studied Buddhist literature. However, Hung-jen sent him with the words "This barbarian is too impudent and should not speak anymore" to the kitchen for work. Hui-neng worked there for eight months without meeting the patriarch.
During that time the patriarch gathered his students and asked them to formulate their understanding of the teaching in a verse. Among the students was Shen-hsiu, a scholar of Buddhism, who thought that this task was to test whether he was suitable to succeed the patriarch. He wrote on a wall of the monastery:
Our body can be compared to the Bodhi tree (tree of wisdom) and our mind with a mirror bright. Carefully we wipe from hour to hour and let no dust alight.
When the patriarch saw this verse, he recognized that Shen-hsiu had not yet experienced universal consciousness and had not yet passed through the "gate of enlightenment" and explained to him: "Those who attain supreme enlightenment spontaneously recognize their own nature or spirit essence. It cannot be created or destroyed." He should recluse himself and think about it. But Shen-hsiu left the monastery and founded his own school of the "Gradual Way", later called the Northern School.
There is no Bodhi tree
Hui-neng also heard about the verse, and since he could neither read nor write, he asked one of the monks to read it to him and did not recognize enlightenment or universal consciousness in these words. But the Universal Consciousness awakened within himself, so he asked the monk to write down the following:
There is no Bodhi tree, nor stand of a mirror bright. Since all is void, where can the dust alight?
The monks and scholars of the monastery were amazed at the depth and wisdom of the verse. But the patriarch wiped it off the wall without saying anything. Secretly, however, he met with Hui-neng and told him that he would make him his successor, the sixth patriarch. However, since he could not appoint a "kitchen boy" as his successor without causing unrest in the monastery, Hui-neng was to leave the monastery and retire for a few years. He gave him the following words:
For him who does not know his own Mind (universal consciousness), there is no use of learning Buddhism. On the other hand , if he knows his own Mind and sees intuitively his own nature, he is a hero, a teacher of gods and men, a Buddha.
Hui-neng could neither read nor write, had not studied Buddhist literature, but had intuitively recognized the essence of Buddha's teachings and Buddhism and had entered universal consciousness. He understood that the essence of enlightenment is that "seeing without seeing", that "hearing without hearing". The difference between these two views - that of the gradual path and that of sudden awakening – gave rise to a long-lasting debate between Buddhist scholars.
The point of emptiness
Hui-neng settled in the monastery in his time and began to teach about the universal consciousness. He explained that doing both good and bad deeds leads to adherence to form. They are the two sides of a medallion, lead to rebirth and do not help to attain universal consciousness. His teaching therefore does not contain any instructions, exercises or ritual acts. Through dialogues about the impossibility of finding the universal consciousness with the ordinary intellect (mind) or through good or bad actions, he led his students to a point of emptiness, of sudden recognition that cannot be put into words: "... the spirit essence is the substance you see before you – just start judging it and you will fall into error". Here we find parallels, to the words of Jesus Christ: "My kingdom is not of this world" (Gospel of John, chapter 18) and to the saying of Paul: "Flesh and blood cannot inherit the kingdom of God" (First letter to the Corinthians, chapter 15).
Overcoming the world of opposites or "phenomena" is done through the intuitive grasp of universal consciousness:
To practice a myriad of practices ... means to progress along the steps, but the Buddha who has always existed is not a Buddha of steps. Awaken to universal consciousness and realize that there is nothing ... to achieve. This is the true Buddha. The Buddha and all living beings are universal consciousness and nothing else.
Hui-neng thus contradicted Shen-hsiu's view that there was a mirror that had to be cleaned carefully. He advised the student who wishes to understand the true secret to "banish the spirit's attachment to whatever. The ordinary people look outward, while those who walk the path look inward”. ("The kingdom of God is within you", Gospel of Luke, chap. 17).
True awakening consists in forgetting (overcoming) the outer and inner, thus entering into universal consciousness. Hui-neng explains that ordinary people are afraid of losing their minds, not knowing that emptiness is not really empty, but the true kingdom of enlightenment, of being in no-being.
Neither intellectual speculation nor actions that have a specific goal can bring us closer to universal consciousness. The Buddha is characterized by the intuitive realization of the non-existence of duality, of not being separate. Since you are basically perfect in every way, you should not seek to complement this perfection with external practices and rites.
From this arises spontaneous action that does not expect results, as is also described in the Bhagavadgita: Purpose- and speculation-free action, which arises from itself, characterizes the one who has recognized and realized universal consciousness.
Hui-neng and his successor Hung-po thus belong to the chain of world teachers who point out that there is something more comprehensive than the visible and invisible worlds that cannot be explained from them: the kingdom that is not "of this world": the universal consciousness. At the end of his life Hui-neng left the words to his disciples:
He who seeks the Buddha (from without) by practicing certain doctrines, knows not where the real Buddha is to be found. He who is able to realize the truth within his own mind has sown the seed of Buddhahood.
He who has not realized the essence of mind and seeks Buddha from without is a fool motivated by wrong desires! I have hereby left to posterity the teaching of the Sudden School, for the salvation of all sentient beings who care to practice it.
Hear me, future disciples! Your time will have been badly wasted if you neglect to put this teaching into practice. 
 D.T. Suzuki: The Zen doctrine of no-mind, Weisser Books, York Beach, Maine USA,1972, p. 130-131.
Mind (with a capital letter M) is understood as the original mind or the universal consciousness. “While listening to Hui-neng, Chi-ch’eng’s (a disciple) mind at once grasped … what his original Mind is.” (ibid. p.19)
 The Diamond Sutra and the sutra of Hui-neng: translated by A.F. Price and Wong Mou-lam; Shambhala Boulders, 2005, pp. 67 – 78.
 Ibid p. 152