Too many angry thoughts of revenge & animosity (hatred) inside our consciousness can
emerge in two ways:
a) either externally as toxic, violent behavior, which will attract toxic, violent responses from others,or
b) if these thoughts are kept bottled inside, they will eventually, after a period of time, emerge as some disease or the other in the physical body. This is because our consciousness then tries to find a way to get rid of the mental impurity, which enters our physical body & restores balance to the mental & physical system, which has been upset due to the creation of the toxic thoughts, in the first place.
