Numbers 5
1 And the LORD spake unto Moses, saying,
2 Command the children of Israel, that they put out of the camp every leper, and every one that hath an issue, and whosoever is defiled by the dead:
3 Both male and female shall ye put out, without the camp shall ye put them; that they defile not their camps, in the midst whereof I dwell.
4 And the children of Israel did so, and put them out without the camp: as the LORD spake unto Moses, so did the children of Israel.
While your quote may be correct it is being used out of the context of this article.
It sure is interesting that the hygiene rules they followed kept them healthy even before people knew about germs.
Too bad the medical community in Simmelweis’s day didn’t follow some of those guidelines. It would have saved a lot of lives. Instead they laughed at him for asking them to wash their hands.