Rumi 鲁米 (1207–1273) is the Persian Sufi mystic（苏菲神秘主义）, poet, and scholar, widely regarded as one of the greatest spiritual poets of all time. 
有一首Rumi诗被很多作家和励志书引用过—“The one thing you must do”.
下面是我根据Coleman Barks英译本做的汉译，与君共勉。
There is one thing in this world which you must never forget to do. If you forget everything else and not this, there is nothing to worry about, but if you remember everything else and forget this, then you will have done nothing in your life.
世上有一件事，你万不可忘记。
若你把别的全抛在脑后，只记得这一件，就不必在意；
但你若把旁的一切都记得，却偏把这件事遗落——
那这一生，你便等于什么也没有完成。（佛老 译）
鲁米卖了好大个关子——他说的这件一生不可不做的事究竟是什么？
It is as if a king has sent you to some country to do a task, and you perform a hundred other services, but not the one he sent you to do.
So human beings come to this world to do particular work. That work is the purpose, and each is specific to the person. If you don’t do it, it’s as though a knife of the finest tempering were nailed into a wall to hang things on. For a penny, an iron nail could be bought to serve for that.
就像国王派你去某地执行一项任务
你到了那里，做了上百件其他小事
却唯独忘了那件他对你的托付
那个托付就是目的啊——
每个人来这世上，都有一个只属于自己的来意
若你没有完成
就好像把一把精钢匕首
钉在墙上当挂钩
明明只要一个铜钱买一根普通铁钉
就够那用途了 （佛老 译）
原来鲁米说的是你的使命、目的，多少人忘记了或找不到？
Remember the deep root of your being, the presence of your lord. Give your life to the one who already owns your breath and your moments. If you don’t, you will be like the one who takes a precious dagger and hammers it into his kitchen wall for a peg to hold his dipper gourd. You will be wasting valuable keenness and foolishly ignoring your dignity and your purpose.
记住你生命最深处的根——
你的造物主的本真
把你的生命交付给那位
早已握着你呼吸与分秒的人
若你不愿
你就会像那个愚昧的人——
手握一柄珍贵的匕首
竟生生钉在厨房墙上
只为挂一个长柄葫芦
天赐的锋芒被浪费
你的尊严和目的
白白虚掷 被辜负
（佛老 译）
这就是鲁米在七百多年前给人的忠告，活一世，只有一件事。
My dear friends, do not waste your talent; never ignore your purpose on earth! – Foulao