21 Or “girls.” The Hebrew indicates they would be female children, making the selection easy.
22 Heb “who have not known [a] man by lying with a man.”
23 Many contemporary scholars see this story as fictitious, composed by the Jews during the captivity. According to this interpretation, the spoils of war here indicate the wealth of the Jews in captivity, which was to be given to the Levites and priests for the restoration of the sanctuary in Jerusalem. The conclusion drawn from this interpretation is that returning Jews had the same problem as the earlier ones: to gain a foothold in the land. Against this interpretation of the account is a lack of hard evidence, a lack which makes this interpretation appear contrived and subjective. If this was the intent of a later writer, he surely could have stated this more clearly than by making up such a story.

In other versions

But all the young girls who have not known man by lying with him keep alive for yourselves.

but save for yourselves every girl who has never slept with a man.

but keep alive for yourselves all the young females who have not gone to bed with a man.

Only the young girls who are virgins may live; you may keep them for yourselves.

But all the females who have not had sexual intercourse with a man, keep alive for yourselves.

But all the women children, that have not known a man by lying with him, keep alive for yourselves.

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