Prior to the death of Yaakov Avinu, he shares his apprehensions with his children regarding the future. Concerning Shimon and Levi, Yaakov declares (Bereishis 49:6) bisodam al tavo nafshi, into their conspiracy, may my soul not enter. The Gemara (Sanhedrin 109b) interprets this verse to be referring to the meraglim. What secret is Yaakov concerned about? When the meraglim return from spying out the land, it is said (Bamidbar 13:26) vayeilchu vayavou el Moshe vel Aharon vel kol adas bnei yisroel el midbar paran kadeisha vayishivu osam davar ves kol haeidah vayarum es pri haaretz, they went and came to Moshe and to Aharon and to the entire assembly of the Children of Israel, to the Wilderness of Paran at Kadeish, and brought back the report to them and the entire assembly, and they showed them the fruit of the land.
Why does it state vayishivu osam davar ves kol haeidah, and brought back the report to them and the entire assembly, which implies that there were two different reports? The commentators (See Ohr HaChaim Ibid) explain that the spies returned and informed Moshe and Aharon one report and then they turned to the Jewish People and offered them a different report. This then was the essential sin of the spies, as they were not truthful to Moshe and Aharon. Had the spies informed Moshe and Aharon that the land was deficient and they could not conquer it, they may have been accused of cowardice but at least their tale would have been plausible. Once the spies stooped to deceit, by telling Moshe and Aharon that the land was good and its fruits were beautiful, they had no right to turn and tell the Jewish People negative information regarding the land. Yaakov foresaw this tragedy and in one word he prophesized regarding the entire scenario. Bisodam, in their conspiracy, may my soul not enter. Yaakov, the quintessential ish emes, man of truth, would have nothing to do with this conspiracy. An allusion to this explanation can be found in the words of the Baal HaTurim, who writes (Bamidbar 13:10) as follows: the word sodi (Gadiel Ben Sodi, the spy from the tribe of Zevulun) is found here and in Iyov (19:19) where it is said: tiavuni kol misei sodi, all my confidants detest me. The Baal HaTurim writes that the spies, who were my confidants, as they were sent to spy out the land and reveal its secrets, despised me, for they slandered the land and caused crying for future generations. Thus, we see again that the sin of the spies was that they engaged in a harmful conspiracy, a sod that Yaakov did not wish to have a part in.