Thoughts which you are not at peace with, are the thoughts of another, be that a person or a school of thought. These thoughts do not originate from you because they were never created by you. They belong to the outside world. Appreciate them, respect them and then let them go. They are not who you are.
Let there be space in your mind so that you can create your own thought out of the emptiness in your mind. You will know this thought as having arisen from the space in your mind because you will be at peace with it, even without thinking if you are at peace with it because it will resonate with the most deepest and silent part of you, where words do not reside.
Make a little space in your mind. Be at peace.