Generally, refreezing thawed meat is not recommended. This is because the quality of the meat will be reduced in this process. Also, if the meat was not thawed in the fridge, there is a strong likelihood that bacteria has started to grow on the meat.
It is best practice to cook the thawed meat, then freeze it.
Food safety is an important concern when deciding to refreeze previously frozen meats. This is a page about refreezing frozen hamburger.