כִּֽי־גֵרִ֨ים אֲנַ֧חְנוּ לְפָנֶ֛יךָ וְתוֹשָׁבִ֖ים כְּכָל־אֲבֹתֵ֑ינוּ כַּצֵּ֧ל ׀ יָמֵ֛ינוּ עַל־הָאָ֖רֶץ וְאֵ֥ין מִקְוֶֽה׃
因為我們在你面前是寄居的，是暫住的，正如我們的列祖一樣；我們在世上的日子如同影子，毫無指望可以長存。
Rashi
For we are strangers before You and we have no share or inheritance in the land and not a possession, only to live in it. An example is (Lev. 25:23): “...for you are only strangers and inhabitants with Me.”
Rashi
like all our forefathers A man who has sons and estates and has sold all the estates, if his sons come to live in that estate days and years later, they are called strangers and inhabitants, but our forefathers were guests. And so did David say: We are not so, but both we and our forefathers are all strangers and inhabitants in the world, as it is written (Ps. 89:12): “The heaven is Yours, even the earth is Yours; the inhabited earth and the fullness thereof, You founded them.”
Rashi
as a shadow are our days on the earth It is explained in Midrash Koheleth (Ecc. Rabbah 1:2): “Not like the shadow of a tree and not like a flying bird, which casts a shadow for days or years or casts a shadow for one hour, but like the shadow of the wings of a bee, which has wings but has no shadow.”