first importance

1 Corinthians 15:1-10
1Now I would remind you, brothers, of the gospel I preached to you, which you received, in which you stand, 2and by which you are being saved, if you hold fast to the word I preached to you— unless you believed in vain. 3For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, 4that he was buried, that he was raised on the third day in accordance with the Scriptures, 5and that he appeared to Cephas, then to the twelve. 6Then he appeared to more than five hundred brothers at one time, most of whom are still alive, though some have fallen asleep. 7Then he appeared to James, then to all the apostles. 8Last of all, as to one untimely born, he appeared also to me. 9For I am the least of the apostles, unworthy to be called an apostle, because I persecuted the church of God. 10But by the grace of God I am what I am, and his grace toward me was not in vain. On the contrary, I worked harder than any of them, though it was not I, but the grace of God that is with me.

News
The gospel is not advice about what we must do but good news about what Jesus has done. The gospel is not a list of instructions to be acted on, it is a message that is preached (v1, 2) and received (v2). This is good news because our acceptance by God doesn’t depend on our performance but on Jesus’ performance in our place.

Substitution
Paul describes this news of first importance: that Jesus died [in our place for our sins] and was raised from the dead. Our sin is that we try to substitute ourselves for God. God responded by substituting himself for us

Biblical
The message of the gospel is “according to the scriptures” (v3&4). It is the primary theme of the entire bible, from God’s response to Adam and Eve’s sin in Genesis 3:15, to the crowds singing about the Lamb who was slain in Revelation 5:12. Christianity is not about shaping God in our own image. God has told us what he is like. We respond to that revelation.

Transformational
This gospel changes people, including those people mentioned in this passage. Cephas (Peter) was transformed from denying Jesus to a bold preacher of Jesus death and resurrection. The 12 were changed from an uncertain group in hiding to fearless martyrs for the faith. James started off thinking is brother was mentally unstable and ended up worshipping him as God. Paul set off on a journey to arrest and persecute Christians and spent the rest of his life planting churches.

This gospel transformation is not just a one-off change but continues through our entire lives. Paul is writing this to Christians. He is reminding them of the gospel v1. He says it is the message “by which they are being saved” v2. Our failure to grow is down to our failure to remember and believe the gospel.

Grace
We contribute nothing to this other than our sin. It is a total gift of God’s grace. We don’t need to clean ourselves up first, which is good news because we wouldn't be able to! This unconditional love seems to be too good to be true, but if it leads us to think we can live in any way we want, we do not understand it. God’s grace changed Paul so that he could say “I am what I am” v10 (an apostle that didn’t deserve to be), and that “God’s grace to me was not in vain”v10. We don’t obey in order to be loved by God. He loved us first, and that love motivates us to obey.

Paul is writing this to remind Christians of the gospel. The gospel is not just for non-christians. We don't respond to the gospel once and then move on, we move on in the Christian life by our ongoing response to the gospel.