As Yaakov Avinu is sleeping and dreaming of the malachim going up and down the ladder, Rashi explains that it is Hashem who is guarding over him.

The Aish Kodesh asks, why is it Hashem guarding over Yaakov and not a malach? Why does it repeat that he is being guarded twice?

The Malachim of the ladder represent the nations of the world who are at war with each other. When they are fighting, Klal Yisrael is in danger. In these times we need the special shemira of Hashem Himself. When we have no zechusim of our own, we are still the children of the Avos and Hashem watches over us in their merit. 

The Rebbe explains that there is a difference between that which is written and that which is spoken. That which is spoken does not last but that which is written can be taken with us. The Rebbe calls upon us, in times of great struggle, to write our inspiration on our hearts so we can take it with us.