Bava Batra 164 - 170
Rav Dimi the brother of Rav Safra taught, “A person should never speak words of praise of another person, since his speech about the person’s goodness will lead to speech about the person’s disgrace.”
What’s wrong with praising someone? The Chafetz Chaim in his sefer called “Chafetz Chaim” (9:1) explains this as follows: Speaking excessive praise of another is forbidden because this will lead the speaker to eventually speak disparagingly of the person. For example, he will say about the person: “… except for one certain bad trait that he has”, or the listeners of this excessive praise will respond: “Why do you praise him so much? But he has a certain bad trait!”
The Chafetz Chaim notes that the gemara is in fact only forbidding speaking excessive praise of a person to another person, since we find in the Talmud cases where Sages would praise the character traits of others — meaning that non-excessive praise is certainly permitted. See for example how Rabban Yochanan be Zakkai would recount the praise of each of his five top students (Avot 2:9). The Chafetz Chaim notes that this explanation of the gemara as forbidding only excessive praise is also found in the commentaries of Rashi, Rashbam and the Rif.
- Bava Batra 164b
Rav Amram said in the name of Rav, “There are three transgressions that a person is not saved from each day: contemplating transgression, ‘looking into’ prayer, and a subtle form of evil speech.
The actual text of the gemara for these transgressions is: hirhur aveira, iyun tefilla and avak lashon hara. The Rashbam defines the second and third transgressions. He writes that an example of avak lashon hara (literally, the dust of evil speech) is saying to another person with a negative implication, “Where is there always a fire for cooking? In the home of so-and-so!” This implies that the person is rich and he is cooking food there all day long. Iyun tefilla is explained by the Rashbam as: “After a person prays, he judges in his heart that
This reminds me of a story I heard recently. A woman was married for ten years without having children, despite her numerous, tearful prayers. She went to Rav Shlomo Zalman Auerbach (zatzal). She cried out her story to him. He told her, “G-d doesn’t owe you children”. She began to leave in a state of overwhelming despair. Rav Shlomo Zalman called the woman back, saying, “G-d doesn’t owe you children, but He can certainly give you more than He 'owes' you — if you take upon yourself more than your basic obligation. Then maybe He will do for you more than He 'owes' you. The woman took these words to heart, and started volunteering at three hospitals in her city. Within a few years, she had one child and then twins, and has continued her volunteering to this day.
- Bava Batra 164b