Gen. 28:20-21 if God will.

remove the if and you have God's will.  This that he reafirms is the promises already made to Abraham.
When one feels guilty he doesn't feel deserving of God's blessings.  Many mistakes are over looked by God's mercy. 
It has a sense of humor about it.  He is going to take Esau's blessing and run off not knowing if he deserves it .  He tricked Esau.  Well if God is with you  then you will know if your blessed. Make sure your heart is right with him.  I personally believe a God who is displeased will not be able to do much for us. He can send grace to bring about our repentance though.
This seems  to be the way that people see God.  One who supplies for us and we are dependant on him.
That is a good thing. We will be very blessed when we commune with him and worship in a deep way. Falling in love with him is far better than anything else. The benefits just seem to come to us as we do.

Gen. 27: fat will dew

God would give abundance of prosperity to him.  When hands were laid on him he did not receive  the literal things into his body. I know that sounds funny. cattle was not inside him.  money wasn't all of the sudden found inside him.  The Old Testament saints laid hands on the innocent victim and they were transferring the sins onto the scapegoat.  He was taken out of the city and then that was a symbol that the sins were carried away. 
Therefore we see that sins didn't literally go into Jesus but were carried away as he was a substitute who took the punishment for the sins. 
Jacob would receive his blessings one day at a time throughout his life. They came to him--- not out of him.  see--- symbolism is sometimes misinterpreted as literal.   When we drink the cup and eat the bread it is a symbol, not literal as the Catholic priests  proclaim.  They say the blood when swallowed becomes real blood.  Someone said to me ,how can my sins go back and be on him when I sinned in this century.
God wants us to be fat with blessings and have the dew of heaven.  He didn't mean have to sleep outside and be covered with dew in the morning.  Rain and dew are symbols of prosperity and abundant grace.