In this little section of Peter's letter are some comments that people have been scratching their heads over for centuries. Scholars have differing opinions on what Peter meant when he said Jesus preached to imprisoned spirits after his death, and before ascending into heaven. While that part may not be clear, the rest of this passage is crystal clear on what Jesus did for us. He died for all sins, he died in our place, he died once and for all, and in all that, he brought us to God.