Sources from the Teshuva on Providing References

(7) Keep thee far from a false matter; and the innocent and righteous slay thou not; for I will not justify the wicked.

(14) Thou shalt not curse the deaf, nor put a stumbling-block before the blind, but thou shalt fear thy God: I am the LORD.

(16) Thou shalt not go up and down as a talebearer among thy people; neither shalt thou stand idly by the blood of thy neighbour: I am the LORD.

This is the penalty for the liar, even when he tells the truth, no one believes him

For a teacher has said : Teach your tongue to say, "I do not know," lest you invent something and be trapped.

The Sages said: "For three sins, a person is punished in this world, and has no place in the World to Come: idolatry, incest/adultery, and murder - and slander is like all of them combined.

Great is the duty of honouring one's fellow-creatures, since it sets aside a prohibition enjoined by the Torah.

(10) Just as there is fraud regarding commerce, so too there is fraud regarding words. One should not say to [a merchant], "How much is this object?" if one does not want to buy. If someone was a penitent, one should not say to them, "Remember your former actions." If someone is the child of converts, one should not say to them: "Remember the deeds of your ancestors." As is written (Exodus 22:20): "You shall neither deceive a stranger, nor oppress them."

Rather it is to say that your "yes" be yes and your "no" be no. Abaye said that means one should not speak one thing with the mouth and another with the heart.

Our Rabbis Taught: How must one dance [or praise] before a bride?

Beit Shammai said: [say] the bride as she is.

Beit Hillel said: [say] "'O bride, beautiful and gracious"

Beit Shammai said: If she is lame or blind, is one to say "O bride, beautiful and gracious"?!?! Does it not say in the Torah, "Keep far from a falsehood"?

Beit Hillel responded: "according to your words, when one makes a bad purchase in the market, is one to commend it or disparage it? Surely one should commend it,"

From here the wise say, "always make your disposition sympathetic to others"

And Rabbi Ile’a said in the name of Rabbi Elazar, son of Rabbi Shimon: Just as it is a mitzva for a person to say that which will be heeded, so is it a mitzva for a person not to say that which will not be heeded. One should not rebuke those who will be unreceptive to his message.

Rabbi Abba says: It is obligatory for him to refrain from speaking, as it is stated: “Do not reprove a scorner lest he hate you; reprove a wise man and he will love you” (Proverbs 9:8).

And Rabbi Ile’a further said in the name of Rabbi Elazar, son of Rabbi Shimon: It is permitted for a person to depart from the truth in a matter that will bring peace, as it is stated: “Your father commanded before he died, saying: So you shall say to Joseph: Please pardon your brothers’ crime, etc.” (Genesis 50:16–17). Jacob never issued this command, but his sons falsely attributed this statement to him in order to preserve peace between them and Joseph. Rabbi Natan says: It is a mitzva to depart from the truth in order to preserve peace, as it is stated: “And Samuel said: How can I go, and Saul will hear and kill me” (I Samuel 16:2). God responded in the next verse that Samuel should say he went to sacrifice an offering, indicating that God commands one to lie in order to preserve peace. It was taught in the school of Rabbi Yishmael: Great is peace, as even the Holy One, Blessed be He, departed from the truth for it. As, initially it is written that Sarah said of Abraham: “And my lord is old” (Genesis 18:12), and in the end it is written that God told Abraham that Sarah said: “And I am old” (Genesis 18:13). God adjusted Sarah’s words in order to spare Abraham hurt feelings that might lead Abraham and Sarah to quarrel.