同舟敌国

Explanation: People help each other become enemies. 　　Source: "Sun Zi Qi Historical Biography" If you not virtue, a boat person to do for the enemy too. " 　　Examples: Injustice has been lost by parents for several years, missed the pillow Gesi reported sigh. ~ This encounter, but also across the river mountain thousands. (Ming Feng Meng, "Awaken the common saying" Volume 16)