Argument that the dead can still be saved:
"I tell you the truth, a time is coming and has now come when the dead will hear the voice of the Son of God and those who hear will live. For as the Father has life in himself, so he has granted the Son to have life in himself. And he has given him authority to judge because he is the Son of Man. "Do not be amazed at this, for a time is coming when all who are in their graves will hear his voice"
(John 5:25-28)
"...through whom also he went and preached to the spirits in prison who disobeyed long ago when God waited patiently in the days of Noah while the ark was being built..."
(1 Peter 3:19-20)
"He died for us so that, whether we are awake or asleep, we may live together with him."
(1 Thess. 5:10)
"But they will have to give account to him who is ready to judge the living and the dead. For this is the reason the gospel was preached even to those who are now dead, so that they might be judged according to men in regard to the body, but live according to God in regard to the spirit."
(1 Peter 4:5-6)
"Now if there is no resurrection, what will those do who are baptized for the dead? If the dead are not raised at all, why are people baptized for them?"
(1 Cor. 15:29)