Classical grammar words in the Dao De Jing
矣 yǐ
In the Dao De Jing, 矣 (yǐ) is a final particle of completion or result, used 10 times: it marks what has come about or will surely follow, much like modern 了.
矣 is a particle placed at the end of a sentence. It presents what the sentence says as a change that has happened or a result that will follow: 故终无难矣 (chapter 63), “and so in the end has no difficulty.”
Its closest modern equivalent is 了 at the end of a sentence, which has replaced it; today 矣 appears only in quotations and in set phrases such as 足矣, “that is enough”.
矣 as “final particle (completion, emphasis)”
Pattern result + 矣
A final particle of completion or result. It closes a clause that states an outcome, often after 故 “so” or 则 “then”: 故抗兵相加，哀者胜矣 (chapter 69), “So when armies meet, the side that grieves will win.” It can also make a description emphatic, as in 玄德深矣，远矣 (chapter 65), “Mysterious virtue is deep, is far-reaching.” English usually leaves it untranslated.
10 times in 9 lines.
则不可得志于天下矣。
cannot achieve his aims in the world.
Chapter 31, line 10故知足之足，常足矣。
So the contentment of knowing what is enough is lasting contentment.
Chapter 46, line 5故终无难矣。
and so in the end has no difficulty.
Chapter 63, line 12玄德深矣，远矣，
Mysterious virtue is deep, is far-reaching,
Chapter 65, line 8与物反矣，
it turns back with all things,
Chapter 65, line 9若肖，久矣其细也夫！
If it resembled something, it would long since have become small!
Chapter 67, line 4
Show 3 more lines
舍后且先，死矣！
to give up being last yet be first: this is death!
Chapter 67, line 13故抗兵相加，哀者胜矣。
So when armies meet, the side that grieves will win.
Chapter 69, line 7希有不伤其手矣。
rarely escape cutting their own hands.
Chapter 74, line 11
How to tell them apart
Compare 矣 with 也, the other common final particle. 也 states what is, a fixed judgment; 矣 states what has become or will become. A line that ends in 矣 can usually take “now” or “then” in English: 死矣 (chapter 67), “this is death!”, is death as the outcome of the course just described.
Look also at the start of the sentence: a 故 “so” or a 则 “then” there is a strong sign that the 矣 at the end marks a result (chapters 31, 46, 63 and 69).