It is striking that Peter does not say here that Noah and his family were saved; that is, he does not list the actual family as was done in Genesis 6:18, Genesis 8:18. Peter emphasizes the notion of “few” and then even specifies how few: a mere “eight persons” from the entirety of mankind (estimated to number into the hundreds of millions in the period before the flood). Though the spirits (demons) were imprisoned, they yet managed to cause the death of the entire human race except for a mere eight persons.
20 because they formerly did not obey, when God’s patience waited in the days of Noah, while the ark was being prepared, in which a few, that is, eight persons, were brought safely through water.