Reading gives us knowledge. Doing gives us experience. It is not something that you do not know.
Why we say so?
Reading - I read a book and understand the contents. For people like me it would take 5-6 reads to understand. But i will never be able to understand it completely (read a book that tells benefits of waking up at 5am).
Doing - When i do it, i understand it more. When i understand it more, i am closer to perfection than mere reading (do it few times here and there, see the benefits yourself).
Habit - Do it consistently takes me a lot closer to perfection and the returns are huge (make it a habit and reap the fruits).
Success lies in reading something, doing it to understand it and making it as an habit.