Joseph Smith claimed he understood 1 Peter 4:6, which says in part, “For this cause was the gospel preached also to them that are dead.” The New International Version translates the last portion of this, “the gospel was preached even to those who are now dead.” While the word now is not found in the original Greek, it was used by the translators because the context suggests that the preaching of the gospel had been delivered in the past to those who were now deceased. In order to support the Mormon view of a second chance to hear the gospel message and receive salvation after death, the first verb would need to be present tense (i.e., “for this cause is the gospel preached also to them that are dead”).
Peter said in the context (verse 5) that those who were living evil lives and causing problems for these first century Christians were going to be judged. He then moved back into the past tense, explaining that those who were already dead had the truth preached to them when they were alive. While Peter explained in the previous chapter (3:19) how Jesus “made a proclamation to the spirits in prison,” there is no indication that this meant these spirits could accept the gospel. To say that salvation can take place after death goes against the Bible’s teaching, as Heb 9:27 and 2 Cor 6:2 state that there are no second chances. As a matter of fact, Alma 34:31ff in the Book of Mormon states that there no works are acceptable after this life.