I'm afraid that there are no any idioms with the same meaning if we are talking about "Words" and "the power of words". More to say, in the Russian language all idioms that I know have the opposite meaning :) We like to say that words are the most powerful thing against other people, so if you want to kill mentally a Russian person, just say to him something offensive :)
But in the life speech you can hear the phrase "Ваши слова ничего не значат для меня" or "Ваши слова не имеют для меня никакого значения". It translates into English like "Words you said have no meaning for me".
P.S.: Sorry, I asked my mother about it, and she said me the expression "Собака лает, ветер носит" or "Собака лает, а караван идет", which means "The dogs bark, but the caravan goes on".