Would Jesus promote punishing the innocent instead of the guilty?

[Vicki Q]

The detail? Paul only claims to know nothing except "Jesus Christ, and him crucified" (1 Cor. 2:2)

Clearly that's not supposed to be taken literally (did he also act like he didn't know his name?). Paul means that he had the gospel, with its crucified Messiah, as his singular focus and passion while he was among them.

and reminds them that Christ died for our sins, was buried, and raised on the third day – three details he knows because they are "according to the scriptures" (1 Cor. 15:3–4).

I'm not sure what your point is here, I'm afraid.

After Jesus' resurrection, the disciples went back to the OT writings and were able to clarify things that were rather vague before. The promise to Abraham was never meant to be just to one nation about just a patch of the Middle East. It was to humanity, about the world. The suffering servant of Isaiah, something of an interpretive mystery, turned out to be Jesus representing Israel. God's promise to return to Jerusalem, enacted in the 'Palm Sunday' events, suddenly became clear.

Paul refers directly and indirectly to the OT story throughout his letters. For example, in Romans 9 he is analysing the ongoing Jew/Gentile divide by looking at both the wider story and specific OT passages. He is treating the OT much like the early acts of a play, to which the later acts must be faithful.

Continuity? How? By listing so called Jesus's genalogy?

Yes. The genealogy is intended amongst other things to emphasise that Jesus follows the OT story.

Or maybe when they were making truly ridiculous claims that OT passages describe Jesus? Like one of the most notorious ones is Matthew 2:16-9, where its author claims how Jeremiah 31:15 in which Rachel is crying for her children is a reference to Herod's slaughter of the Innocents.  

Please read the whole of Jeremiah 31, because Matthew is using this verse as a kind of tag for the whole thing. J31 tells of God's renewal of the covenant, bringing Israel back from exile. Although Israel will need to mourn, as has happened so often in its history, once again rescue is on the way.

Verses 31-34 are particularly important in that there is a clear promise that this renewal will be completely different, completely great and completely final. Matthew is saying 'It was always going to be the case that this sort of suffering comes as an unwelcome part of the bundle”.