同病相怜（同病相憐）　

◎ 同病相怜 tóngbìng-xiānglián

[fellow sufferers have mutual sympathy;those who have the same illness sympathize with each other;adversity makes strange bedfellows;company in distress makes trouble less;fellow sufferers commiserate with each other] 比喻因遭遇同样的不幸而共相怜恤

同病相怜,同忧相救。——《吴越春秋》