Warren Buffett wasn't afraid to buy when others were selling. As one of the best investors in history, Warren Buffett has uttered many quotable comments over the years. Still, there are two famous Warren Buffett quotes that could apply to Rivian, and both make me excited about Rivian as a long-term investment. Warren Buffett likes buying stocks like RivianIn 2021, Rivian, as a company and as a stock, was doing great. This leads to the second Warren Buffett saying: "The best chance to deploy capital is when things are going down."