Yes, it will—but that's not a bad thing!
You have to remember that some of the potential clients who land on your site will be more comfortable reading text, and others will prefer to sit back in their chairs and watch you explain your expertise.
If they're especially interested, they'll probably do both, watching the video after they've already gleaned from your home page whether you're a good fit for them or not. For this reason, there's no problem with repeating in your video what you already say on your site.
If you're worried about a potential Google search penalty, put your mind at ease—that only applies to pages of your site that repeat (in text) the same information over and over again.
Of course, you need to make sure that what you say in your video reinforces, rather than contradicts, what is written elsewhere on your site, or even on the same page. It will do you no good to plunk a video in which you discuss your divorce-law expertise in the middle of a page devoted to personal injury lawsuits, and you also need to annotate the video in a way that's consistent with the rest of your site.
At the very least, you must give your video a written headline, and provide a brief description underneath telling visitors what the video is about. This will also help the placement of your video in YouTube search results.