by Rav Simcha Klein
1. Shaarei Teshuva (shaar 3 ois 184) “emes hu myesodie hanefesh”. See Chazon Ish (Emunah vBetachon 4:13) “A person who says an untruth once is a sinner, a person who constantly says untruths has developed a flawed essence”. See also Emunah V’betachon (3:30).
2. See Sukkah (46b), Mishnah Torah (Shavuos 12:8) and Sfas Tamim (perek 7).
3. Inevitably the child will observe the parent not being sensitive to the truth and he will be strongly impacted by it, essentially negating all that he hears regarding the importance of truth.
4. A parent, who does want to take a phone call at home for whatever reason, should instruct his child to tell the caller he is not available; never tell him to untruthfully convey to the caller that he is not home. Similarly, parents should always be truthful regarding the precise age of their children when entering museums, amusement parks, and the like even if it will result in a financial loss.
5. Because the child might not realize it was said jokingly, see Mishnah Halochos (vol. 9 siman 344).
6. See Sukka 46b. Such conduct teaches the child that one doesn’t need to take their own words seriously,
7. Advice of the Shelah HaKadosh (shaar hosios ois daled); see also Pele Yoetz (erech sheker).
9. However, depending on the age of the child, you should definitely point out to him that what he is saying is imaginative; see Rav Matisyahu Solomon Shlita in “With Hearts Full of Love” (p. 195) .
10. Parents should work very hard in creating a healthy atmosphere at home where children are comfortable sharing their mistakes and failures. See Mayan Bais Hashoaiva (Parshas Vayaishev)
11. Rav Matisyahu Solomon Shlita in “With Hearts Full of Love” (p. 193).
12. See Igeres HaGra. B’mechitzas Rabbeinu quotes Rav Shmuel Kamenetsky Shlita as saying that his father Rav Yaakov Kamenetsky z”l rarely utilized corporal punishment in educating his children except when an untruth was spoken.
13. See Rivivos Efraim (vol.4 siman 234).
14. An illustration of this is to teach the five inuyim of Yom Kippur by counting eating and drinking as two, when in truth they are to be counted as one (marital relations is the fifth).
15. Rav Matisyahu Solomon Shlita in “With Hearts Full of Love” (p. 195). in the name of the Steipler Gaon z”l.