Halakhah su Salmi 106:25

Furthermore, is it not well known that exile had already been decreed upon us because of the act of the spies (viz. Tehillim 106:25-27): "And they murmured in their tents [against the land]. They hearkened not to the voice of the L–rd. And He lifted up His hand [in oath] against them… to scatter them in the lands," as Rashi and the Ramban explain there (Bamidbar 14). And the sin of the spies — was it not that of lashon hara! (viz. Arachin 15a). Therefore, it is imperative that we correct this sin before the redemption can take place.