This discourse was said by the Rebbe on Shabbat Parsha Balak in 1958. It discusses the fact that Balaam's blessing focuses on Jacob (rather than Israel) when he wishes the Jewish people to be as numerous as the dust.  

The idea of being like dust comes up earlier in Sedra Vayetze and it is then that G-d promises him that his descendants will be like the dust of the earth and they will burst out to the west and the east, the north and the south...   Jacob represents the Jewish people and also each individual Jew. Jacob's journey is his or her journey as well.