Bible Verses About Christian prayers for the dead

And when he came to Jerusalem, and had gathered the congregation together, he made an offering for sin, that he might be delivered from sin. And when he made supplication for the dead, that they might be loosed from sin, he was merciful.KJV

Else what shall they do which are baptized for the dead, if the dead rise not at all? why are they then baptized for the dead?KJV

The Lord give mercy unto the house of Onesiphorus; for he oft refreshed me, and was not ashamed of my chain: But, when he was in Rome, he sought me out very diligently, and found me. The Lord grant unto him that he may find mercy of the Lord in that day: and in how many things he ministered unto me at Ephesus, thou knowest very well.KJV