“you shepherds.” In this context, the “shepherds” are the leaders of the people, the people being the “sheep.” So here in Jeremiah, God is announcing that there will be a day of retribution against the evil leaders.
“fall and be broken like a precious vessel.” The Hebrew text simply reads “fall like a precious vessel,” but in the biblical culture the meaning of that would be very clear. “Precious vessels” were thin and delicate, unlike the common cookware that was thick and made to stand up to much use. “Precious vessels” were not put on the floor, and so if a “precious vessel” fell from where it was placed it would shatter into many pieces and be hopelessly destroyed. That is the picture in this verse: the evil leaders will be destroyed.