“…they stumble that run fast.”
I think that this quote can be applied to Romeo and Juliet in the sense that everything is Romeos and Juliet’s relationship happens very quickly. In terms of their relationship they are ‘running fast’; everything happens very quickly, they meet for the first time and decide that they are to be married. Whenever something is rushed or rash decisions are made something usually goes wrong, ‘stumbles’. So I think that this quote is talking about Romeo and Juliet’s fast pace relationship and the fate of the two star crossed lovers.