While the word "blessing" has several different ways it can be used, do you know where all blessings ultimately come from? Do you act according to your knowledge?
As Jacob and Esau fought for blessing, and for birthright, Jacob used trickery and manipulation to try and receive what prophecy from God said would come to him anyway. Jacob failed to trust the knowledge that God would bless him.
Where does the ability come from, to trust God for what you know to be true? I'll give you a clue, the word starts with an 'S'. The work of the Spirit gives life to mere knowledge, making you do crazy things like putting your life on the line for what you know and are convinced of.
The irony of Jacob in this example, is that he knows the blessing ultiamtely comes from God. He even says as much to Isaac when asked how he returned from the hunt so fast, "Because the LORD your God granted me success." - Genesis 27:20