42 Heb “under the sun.”
43 Heb “the second youth.” It is not clear whether “the second” (הַשֵּׁנִי, hasheni) refers to the young man who succeeds the old king or a second youthful successor.
44 The verb עָמַד (’amad, “to stand”) may denote “to arise; to appear; to come on the scene” (e.g., Ps 106:30; Dan 8:22, 23; 11:2–4; 12:1; Ezra 2:63; Neh 7:65); cf. 764 עָמַד 6.a; עמד 1.a.

In other versions

I saw all the living who move about under the sun, along with that youth who was to stand in the king’s place.

I saw that all who lived and walked under the sun followed the youth, the king’s successor.

I saw all the living, who move about under the sun, follow a second youth who succeeds him.

But then everyone rushes to the side of yet another youth who replaces him.

I saw all the living who move about under the sun with the youth; the second who will stand in his place.

I considered all the living which walk under the sun, with the second child that shall stand up in his stead.

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