Subtle Slander

"These are the words that Moshe spoke to all Israel" [Devarim 1:1]

Why, asked the Megaleh Amukos [R' Nosson Nota Shapira] does the verse state "...that Moshe spoke to all Israel" and not simply "...that Moshe spoke to Israel"?

The acronym of the word "eileh" he answered is "avak lashon hara" - the dust of evil speech - subtle types of slander.

Chazal state in Maseches Bava Basra [165b] "Most individuals transgress the sin of theft, a small minority transgress the sin of illicit relations, but all transgress the sin of avak lashan hara."  The grave sin of lashon hara is a sin that all of Israel might come to transgress, so all Jews must be cautioned of the danger it presents.  The verse therefore states: "These are the words that Moshe spoke to all Israel."

Source: Rabbi Yisrael Bronstein