旦日知志,始於足下. "Once you realized/know your goal, you start walking". I am playing with words here. I am alluding to the Chinese saying of Lao Tzu, "A journey of a thousand miles begin with one step". (萬里之行,始於足下) Joa's paraphrase is excellent but does not convey the same sentiment as in the original sentence.

不知原文是否另有引申義? 請賜教 ! 庶幾令譯文正確表達 ! horizon : (知識經驗, 興趣等的) 範圍界限 journey : 過程 一旦感受到自己的知識經驗有限後 你才會了解學習的過程才剛起頭 => 一旦感受到自己的知識經驗不足後 你才會了解學習是必要的 => (學，然後知不足；) 知不足，然後學。

Anyway，I feel confused now. In the beginning， I guess it is a metaphor，so it refers to the original meaning of “horizon” itself，that is， the “ground level ”。You know，in a journey，no matter how far you have walked，the distance between the horizon and you is always the same ，never changed. Before you know what "horizon" is,you assume there is a limitation of the world, so the world is not so big. Only after you found the horizon,you would know the horizon could moving with you! so the limitation of the world doesn't exist in reality. So that suggests no matter how many knowledges you have learned ，you could never know everything。learning doesn't have any limitation or end.Only after you know this thing，you will begin to study or work more diligent，and you will never be arrogant 。you will keep studying for ever，then you have a new meaning of your journey（your life） But then,after reading the others' opinion，I feel a little confused about the original sentence. If horizon means limitation or calling，then my understood maybe wrong. I wish rbyrne11 could give a context.

吾等妄生穿鑿矣 然而 「是不必然，亦不必不然，郢書燕說，固未為無益。」(清 紀昀 語)

当你发现自己的不足之时，就如同行者看到了地平线，你学习的旅程才刚刚开始。