1) MEFIVOSHES -- SON OF WHOM?
QUESTION: The Gemara cites a verse that calls Mefivoshes the son of Shaul (Shmuel II 19:25). Why does the verse call him the son of Shaul when he was really the son of Yehonasan?
(a) The IYUN YAKOV explains that in this incident, Mefivoshes displayed animosity towards David ha'Melech by saying that Hash-m should not have helped him to overthrow Avshalom. Therefore, the verse relates him to Shaul, who also hated David, and not to Yehonasan who loved him.
(b) Since, in this incident, Mefivoshes complained about the way Hash-m was conducting the affairs of the world the same way that Shaul complained (as the Gemara says on 56b), the Gemara relates him to Shaul and not to Yehonasan. (M. KORNFELD)
2) THE SEVERITY OF THE SIN OF "LASHON HA'RA"
AGADAH: The Gemara says that because David ha'Melech accepted words of Rechilus about Mefivoshes (as the verse says, "va'Yeragel b'Avdecha" (Shmuel II 19:28)) and as a result he confiscated half of Mefivoshes' property, Hash-m punished him by taking away half of his kingdom several generations later.
RAV MORDECHAI ARAN in SEFER NIFLA'OS MI'TORASECHA (Jerusalem, 1997) points out that a computer search shows that in only two places in the entire Torah do the "Sofei Teivos" (the last letters of consecutive words) spell out "Rechilus" ("Rechilus" never appears as "Roshei Teivos," an acronym comprised of the initial letters of consecutive words).
The first place is in Bereishis 3:11, where Hash-m asks Adam, "Did you eat from the tree from which I commanded you not to eat?" -- (asheR tzivisiCHa l'viltI achoL mimenU achalTa). The Midrash (Tanchuma Bereishis 8:8) teaches that it was Lashon ha'Ra that brought death to Adam ha'Rishon, who believed the serpent when it told him that Hash-m does not want Adam to eat from the Tree of Knowledge lest man will become as great as He (that is, Hash-m is greedy). Appropriately, the Torah hints this to us through the Sofei Teivos which spell the word, "Rechilus."
The second place is in Melachim I 14:8, where the prophet tells Yeravam, "I have taken away the kingdom from David and given it to you, but you have not kept all the Mitzvos the way David did" (asheR halaCH acharaI b'choL levavO la'asoS). Here, also, the prophet hints that David, although he was nearly perfect, committed one sin -- he believed the Rechilus which Tziva told him about Mefivoshes. The Gemara here says that it was because of that sin that Hash-m divided David's kingdom, as the verse there in Melachim describes!