Silence
Texas Midlands Bank was prepared to foreclose on Toby's land and take it for themselves in order to pump oil out of it. All they needed was for Toby to not make the necessary payments on the land and it would belong to them. With the stolen money from the banks Toby is able to launder it through the casino and pay off the loan to the bank, and in return Toby hires the bank to manage the trust. In doing this the symbol is that Toby has bought the silence of the bank about the money from the casino. The bank keeps its mouth shut about it because they profit from the oil being pumped off the land, which they won't if Toby goes to prison.
Fire
We watch as Hamilton and Parker come upon a cowboy leading cattle away from a fire that threatens them. This is a symbol for the hardship of being a rancher in the 21st century, that it seems quite foolish to do this line of work in the age of technology. He says something along the lines of, "I'm racing a fire to a river with a herd of cattle. No wonder my kids don't want to do this."
Standoff
We watch as Hamilton visits Toby on the farm and suggests to him that they meet again to finish their conversation. This line is a symbol that Hamilton knows Toby is responsible for the bank robberies and ultimately for Parker's death at the hands of Tanner. And "finishing their conversation" means he is going to kill him.
Tanner
Tanner leads Hamilton and Parker after him so that Toby can escape. This leads to Tanner's death. His sacrifice is a symbol of the only thing he could offer his brother and nephews: his life, in order that they may live a better life than he has.
Backhoe
We watch as Toby buries the stolen Ford Taurus he and Tanner had to take after Tanner decided to rob a bank not on their list while Toby finished his meal at a restaurant. He does so with a backhoe on his farm land. This is a symbol that Toby is a man who knows how to deal with major problems, and has a plan to protect his family when bad things happen.
