Truthfulness has the characteristic of non-deceptiveness. In speech, its function is to verify in accordance with fact; its manifestation is excellence…. Without truthfulness, virtue and the following perfections are impossible, and there can be no practice in accordance with one’s compassionate vows. All evil states have in common the transgression of truth…. With truthfulness as a foundation one is able to purify and fulfill the requisites of enlightenment…All the perfections are grounded in truth, clarified by letting go, intensified by peace, and purified by wisdom.
A Treatise on the Paramis, Dhammapala
When one is not ashamed of telling a deliberate lie; there is no evil that one would not do.
Majjhima Nikaya 1.415
Whatever tricks, deceits, wiles or subterfuges he has, he shows them as they actually are to the Teacher or to his knowledgeable companions in the holy life, so that the Teacher or his knowledgeable companions in the holy life can try to straighten them out.
Anguttara Nkaya 8.13
Angulimala’s Statement of Truth
One day, wandering for alms as monk, Angulimala saw a woman in difficult, painful labor. Seeing this Angulimala, who in the past had no qualms about killing people, thought, “Oh, how much people suffer! How much they suffer!”
Returning from his alms round, Angulimala told the Buddha about the woman having difficult labor. The Buddha said, “Go to her and say, ‘Sister, since I was born, I do not recall that I have ever intentionally deprived a living being of life. By this truth, may you be well and may your infant be well!'”
“Venerable sir,” said Angulimala, “since I have in fact intentionally killed many people, wouldn’t I be telling a deliberate lie?”
The Buddha replied, “In that case, go to the woman and say, “Sister, since I was born with the noble birth, I do not recall that I have ever intentionally deprived a living being of life. By this truth, may you be well and may your infant be well.'”
Angulimala then returned to the woman and made his statement of truth. With this the baby was born and both mother and child became well.
Majjhima Nikaya 86
Safeguarding the Truth
Bharadvaja said to the Buddha, “Master Gotama, with regard to the ancient hymns of the brahmans — passed down orally and included in their canon — the brahmans have definitely concluded that ‘Only this is true; anything else is worthless.’ What does Master Gotama have to say to this?”
“Tell me, Bharadvaja, is there among the brahmans even one brahman who says, ‘This I know; this I see; only this is true; anything else is worthless?'”
“No, Master Gotama.”
“And has there been among the brahmans even one teacher or teacher’s teacher back through seven generations who said, ‘This I know; this I see; only this is true; anything else is worthless?'”
“No, Master Gotama.”
“And among the brahman seers of the past, the creators of the hymns, the composers of the hymns — those ancient hymns, sung, repeated, and collected, which brahmans at present still sing, still chant, repeating what was said, was there even one of these who said, ‘This we know; this we see; only this is true; anything else is worthless?'”
“No, Master Gotama.”
“So then, Bharadvaja, it seems that there isn’t among the brahmans, the brahmans’ teachers back seven generations, or the brahmans who created and composed the hymns even one who said, ‘This I know; this I see; only this is true; anything else is worthless.’ If there were a row of blind men, each holding on to the one in front of him: the first one doesn’t see, the middle one doesn’t see, the last one doesn’t see. In the same way, the statement of the brahmans turns out to be a row of blind men, as it were: the first one doesn’t see, the middle one doesn’t see, the last one doesn’t see. So what do you think, as this is the case, doesn’t the conviction of the brahmans turn out to be groundless?”
“It’s not only out of conviction, Master Gotama, that the brahmans honor this. They also honor it as unbroken tradition.”
“Bharadvaja, first you went by conviction. Now you speak of unbroken tradition. There are five things that can turn out in two ways in the here-and-now. Which five? Conviction, liking, unbroken tradition, reasoning by analogy, and an agreement through pondering views. These are the five things that can turn out in two ways in the here-and-now. Now some things are firmly held in conviction and yet vain, empty, and false. Some things are not firmly held in conviction, and yet they are genuine, factual, and unmistaken. Some things are well-liked … truly an unbroken tradition … well-reasoned … Some things are well-pondered and yet vain, empty, and false. Some things are not well-pondered, and yet they are genuine, factual, and unmistaken. In these cases it isn’t proper for a knowledgeable person who safeguards the truth to come to a definite conclusion, ‘Only this is true; anything else is worthless.”
“But to what extent, Master Gotama, is there the safeguarding of the truth? To what extent does one safeguard the truth? We ask Master Gotama about the safeguarding of the truth.”
“If a person has conviction, his statement, ‘This is my conviction,’ safeguards the truth. But he doesn’t yet come to the definite conclusion that ‘Only this is true; anything else is worthless.’ To this extent there is the safeguarding of the truth. To this extent one safeguards the truth. I describe this as the safeguarding of the truth. But it is not yet an awakening to the truth.
“If a person likes something … holds an unbroken tradition … has something reasoned through analogy … has something he agrees to, having pondered views, his statement, ‘This is what I agree to, having pondered views,’ safeguards the truth. But he doesn’t yet come to the definite conclusion that ‘Only this is true; anything else is worthless.’ To this extent, Bharadvaja, there is the safeguarding of the truth. To this extent one safeguards the truth. I describe this as the safeguarding of the truth. But it is not yet an awakening to the truth.”
“Yes, Master Gotama, to this extent there is the safeguarding of the truth. To this extent one safeguards the truth. We regard this as the safeguarding of the truth. But to what extent is there an awakening to the truth? To what extent does one awaken to the truth? We ask Master Gotama about awakening to the truth.”
“There is the case, Bharadvaja, where a monk lives in dependence on a certain village. Then a householder goes to him and observes him with regard to three mental qualities — qualities based on greed, qualities based on aversion, qualities based on delusion: ‘Are there in this venerable one any such qualities based on greed that, with his mind overcome by these qualities, he might say, “I know,” while not knowing, or say, “I see,” while not seeing; or that he might urge another to act in a way that was for his/her long-term harm and pain?’ As he observes him, he comes to know, ‘There are in this venerable one no such qualities based on greed … His bodily behavior and verbal behavior are those of one not greedy. And the Dhamma he teaches is deep, hard to see, hard to realize, tranquil, refined, beyond the scope of conjecture, subtle, to-be-experienced by the wise. This Dhamma can’t easily be taught by a person who’s greedy.
“When, on observing that the monk is purified with regard to qualities based on greed, he next observes him with regard to qualities based on aversion… on delusion: ‘Are there in this venerable one any such qualities based on delusion that, with his mind overcome by these qualities, he might say, “I know,” while not knowing, or say, “I see,” while not seeing; or that he might urge another to act in a way that was for his/her long-term harm and pain?’ As he observes him, he comes to know, ‘There are in this venerable one no such qualities based on delusion … His bodily and verbal behavior are those of one not deluded. And the Dhamma he teaches is deep, hard to see, hard to realize, tranquil, refined, beyond the scope of conjecture, subtle, to-be-experienced by the wise. This Dhamma can’t easily be taught by a person who’s deluded.
“On observing that the monk is purified with regard to qualities based on delusion, he places conviction in him. With conviction, he visits him and grows close to him. Growing close to him, he lends ear. Lending ear, he hears the Dhamma. Hearing the Dhamma, he remembers it. Remembering it, he comprehends its meaning. Comprehending, he comes to be in agreement with it. Agreeing with it, desire arises. With the arising of desire, he becomes willing. Willing, he contemplates (lit: “weighs,” “compares”). Contemplating, he makes an exertion. Exerting himself, he both realizes the ultimate meaning of the truth with his body and sees by penetrating it with discernment. “To this extent, Bharadvaja, there is an awakening to the truth. To this extent one awakens to the truth. I describe this as an awakening to the truth. But it is not yet the final attainment of the truth.”
“Yes, Master Gotama, to this extent there is an awakening to the truth. To this extent one awakens to the truth. We regard this as an awakening to the truth. But to what extent is there the final attainment of the truth? To what extent does one finally attain the truth? We ask Master Gotama about the final attainment of the truth.”
“The cultivation, development, and pursuit of those very same qualities: to this extent, Bharadvaja, there is the final attainment of the truth. To this extent one finally attains the truth. I describe this as the final attainment of the truth.”
Majjhima Nikaya 95