《淮南子·泰族训》
如果诸侯得道，四周的邻国也都会保护他；如果诸侯失道，就只能以自己的边境为边防了。
诸侯得道，守在四邻：诸侯失道，守在四境。
If a feudal lord governs well, neighboring states will protect him; if he does not govern well, his borders will be his only protection.