I would be bold and say that the thought is more powerful than the word. Since it is the thought that gives birth to the word. However the relationship is not that simple. As soon as the thought starts it takes shape in the form of the word (both spoken and unspoken)
In spiritual life if we can channel our thoughts towards the Supreme Goal then we automatically move away from the lower aspects of our being. AS Sri Ramakrishna would say as you move to wards the Eat the West is automatically left behind.
May Mother guide our thoughts towards Her today and always