Christ Crucified For Us And The New Birth Through the Spirit Are the Two Central Foundations of Christianity (1:10-4:21).
Paul begins this section by revealing his concern that the Corinthians are in danger of splitting up into different parties around the teaching of certain leading teachers (1 Corinthians 1:10-17), and concentrating on secondary aspects of that teaching, rather than being united around the one central truth of Christ crucified, the one fact which is central to the Christian message, and around which all should be united, and which points to the One Who alone, by means of what He accomplished there, is effective in bringing about their salvation through the power of God (1 Corinthians 1:18; 1 Corinthians 1:24; 1Co 1:30; 1 Corinthians 2:2; 1 Corinthians 2:4), and is the very foundation of the Christian faith (1 Corinthians 3:10-15).
The crucifixion of Christ, points out Paul, has brought about the raising up of a wholly new situation. The world is now divided into two. On the one hand is ‘the natural man', devoid of the Spirit, taken up with human wisdom, divided, rejecting God's way, despising the cross (1 Corinthians 1:19 onwards leading up to 1 Corinthians 2:14), and on the other ‘the spiritual one', receiving true wisdom from God, trusting fully in the word of the cross, enlightened, the temple of God indwelt by the Spirit (1 Corinthians 2:4-15; 1 Corinthians 3:16; 1 Corinthians 1:24).
The ‘natural man' is the world in Adam, the first man, and as such earthy and without the Spirit and unable to discern the things of God, with no hope of the resurrection to life (1 Corinthians 2:14; 1 Corinthians 15:45-47). The Spiritual One is the last Adam, the second man, the heavenly One, in Whom are found those who are heavenly, Who has given His Spirit to His own so that they might understand the things of God as manifested through the power of the word of the cross, and know the things that are freely given to them of God, and come finally to the resurrection of life (1 Corinthians 2:10-16; 1 Corinthians 15:42-49).
But sadly the Corinthian church, while having become a part of the second, are revealing themselves as still very much taken up with the first. They are divided, looking to earthly wisdom, arguing about different teachers as though they brought different messages, rich and yet poor, reigning and yet not reigning (1 Corinthians 1:12; 1Co 2:5; 1 Corinthians 3:3-4; 1 Corinthians 4:8), neglecting the word of the cross, and the Crucified One, still behaving as fleshly rather than as spiritual (1 Corinthians 3:1-3). They are not allowing the word of the cross to do its work in them.
They need to recognise that the teachers are in themselves nothing, ‘weak and foolish' tools of God (1 Corinthians 1:26-29) who must themselves account to God (1 Corinthians 3:10-15), whose task is to build on the One foundation which is Christ, for they are building the Temple of God, indwelt by the Holy Spirit. It is indeed the one Holy Spirit Who reveals through these teachers the crucified Christ and what He has done and is doing for them (1 Corinthians 2:10-16). For it is one Christ Who has been crucified and through Whom we are being saved.
What should therefore be all important to them is Christ and Him crucified (1 Corinthians 2:2), the word of the cross (1 Corinthians 1:18), foreordained before the creation (1 Corinthians 2:7), the central message they proclaim (1 Corinthians 3:11), and around which they must unite, for it is He who has been made to them the wisdom from God, even righteousness, sanctification and redemption (1 Corinthians 1:30). He is the one foundation on which they are built (1 Corinthians 3:11). The church is one and it is this message that separates them from the outside world which in its folly and blindness despises Him (1Co 1:20-23; 1 Corinthians 2:6; 1 Corinthians 2:8) and what He came to accomplish. Thus must they maintain unity in Him, partaking in His one body (1 Corinthians 10:17; 1 Corinthians 12:12-13), presenting a united witness to the world (1 Corinthians 1:10-12), recognising that they are the one Temple of God (1 Corinthians 3:16), rather than splitting up into a group of different argumentative philosophical groups having lost the recognition that what they have come to believe in Christ is central to the whole future of all things. They need the grand vision.