According to the first chapter of Sh’mot, the numbers of Israelites greatly increased in Egypt.
The Torah relates this by a series of verbs, “they were fruitful, they increased abundantly, they multiplied, they became very mighty” (Ex. 1:1).
Midrashic commentary explains these verbs one by one.
• “They were fruitful” indicates that the women had children every year like trees that produce fruit every season.
• “They increased abundantly” uses a verb that has to do with fish; like fish, they produced swarms of children on each occasion.
• “They multiplied” means that their death rate was lower than that of the Egyptians.
• “They became very mighty” suggests that because they had good health their infant mortality rate was low.
The series of verbs may be a device used for rhetorical effect. It may also explain why the Egyptians felt threatened by them. “There are too many Israelites already, and before long they are sure to push us out” – that seems to have been the feeling.
Not a word of even grudging praise such as “Maybe we can learn from their health measures”.