Translation
having formerly disobeyed when the long-enduring patience
Go to footnote numberof God was waiting in the days of Noah, [days] of the construction of the ark, in which a very small number
Go to footnote number[of souls], that is eight souls, were saved through water, (See comment below)
Go to footnote numberParaphrase
the spirits of those who had disobeyed long ago while the long-enduring patience of God waited during the time required for Noah to build the ark, in which only a tiny number of souls, eight to be exact, were saved by floating on the water.
Footnotes
1: "long-enduring patience"
Helps word studies says this word can be seen as the opposite of “short tempered”, if only we had the phrase “long-tempered” in English.
2
“Puny, tiny” are good ways to render this word in English.
3: "through water"
It is a rich irony that Peter says they were saved by or through water. It was the water that killed everyone else, but for those in the ark, the water participated in their salvation because the ark was designed to float on top of the water.
WHY DID JESUS PREACH TO THEM?
This passage has long been debated because there are at least two things which pull against each other. The primary ones are that 1) the text of 3:19 says Jesus “having gone” in spirit form, to the place where the souls were being held in prison, or possibly to the souls who are now in prison, and 2) Jesus preached, or proclaimed truth to them.
One of these statements needs to be seen in a non-literal way because they cannot both be taken literally.
The statement of Jesus “having gone” to the spirits in prison makes it sound like Jesus did this during the time that His body was dead and in the tomb. That would be a literal and natural reading of that statement.
However, the part about Jesus preaching to them pulls in a different direction. I Peter 4:6 seems to be referring to the same event and refers to it as the preaching of the gospel. The gospel is good news which includes an offer of salvation. If Jesus went to the place where the disobedient souls were being held and proclaimed to them that He was victorious and they were going to be punished, that could hardly be called good news. They would learn soon enough that Jesus was victorious. The part about Him preaching to them, or proclaiming truth to them, fits better if they were living in a human body when He preached to them, but their spirits were in prison after death at the time Peter penned those words. Those that hold this interpretation say that Jesus preached through Noah to those who were being disobedient at that time. That is why the patience of God in the time of Noah is mentioned.
I find it more Biblically acceptable to adjust the timing of Jesus “going” to preach to them, than to say that Jesus preached or proclaimed truth to spirits of dead people who no longer had a chance to repent. The Bible is clear that, while we are alive in this physical body, we have the chance to repent and change direction, but after we die, there is no such opportunity. Therefore, the is no good reason to preach to the spirits of the dead. That is why my paraphrase for verse 19 is rendered, “he proclaimed the truth when He went to those whose spirits are now being held in prison”.
Also, keep in mind that the eight souls that were saved were normal human beings; why should those who were punished be anything different than human beings?