Question: When Did the Church ‘Get’ the Cross?

I recently started going to a small group, and we’re working our way through Acts. Right now, we’re in the second chapter, having just covered where the Spirit has come upon the apostles, leading them to speak in various tongues and for Peter to forsake his cowardly reputation and give the mother of all sermons.

He talks about how Jesus who was crucified is instead Israel’s Lord and Savior, having been raised from the dead by God. So here’s my question, because I’m hoping some readers can chime in:

When exactly does the church start to realize that Jesus’ own death accomplished something?

I ask because, in Peter’s sermon, it’s not at all apparent that they yet understand that Jesus’ cross was part of God’s victory. Peter references it, of course, but it seems like he only does so to point out that Jesus was killed–because guys who never died don’t need to be resurrected.

I’m trying to think of what the apostles knew at this point about Jesus’ death. They would have known that he predicted it, more than once. They could have remembered what Jesus taught them during the Passover meal: his blood would inaugurate the blood of the new covenant. And while the church came to affirm that–St. Paul specifically calls Jesus our Passover Lamb–I’m having a hard time figuring out if the apostles knew the significance of the cross when Peter gave his famous first sermon.

So I’m leaving the question to you all: when did it dawn on the early church that Jesus’ very death had accomplished something? Keep in mind, this isn’t addressing the question of whether it did but rather, when the church finally realized it.

Happy talking!