Negative thoughts are a byproduct of negative emotions like Jealousy, Anger, Greed, Fear, Hatred, Revenge, and Superstition. 

If not checked and replaced by positive emotions, viz., Desire, Faith, Love, Sex, Enthusiasm, Romance, and Hope, mental agony results. 

Emotions, as we know, emanate from the heart, and are pumped all the way to the brain, and from there, to the whole body. 

As carriers of negativity, the havoc they cause to a person and his personality (physical and spiritual), shouldn’t be hard to fathom.

Long story short, feelings or emotions precede thoughts. The cure, therefore, lies in understanding the emotions. If these are positive, purity of thought is guaranteed.

And so is health, wealth, and prosperity.