The idea that has been expressed implicitly in paraagraph 6 is that Noah will be busy working to achieve his dreams and help others.
This is the idea that is present in paragraph 6, even though it has not been directly expressed. Throughout this passage, the author refers to all the activities that Noah is carrying out in order to help others, from designing a driving campaign and working on motivational films to talking with students and writing a book. In that way, what the author tries to indicate to the reader is that Noah is very focused on doing things to help other people, and, at the same time, very focused on achieving his goals.