The entire section may be read as a general contrast between God and men, and between their respective spheres (temporal existence and eternity), with verse 11 being the pivotal statement: "For no man can lay a foundation other than the one which is laid, which is Jesus Christ." If we break this statement down into a nuclear sentence, it becomes something like this: "No man can lay any foundation other than Jesus Christ." If distilled further, the thought may be expressed simply, "Jesus is the foundation." Jesus himself is the ultimate foundation of our faith, our growth, our churches and ministries, and our eternal hope.
A number of key words help to clarify the meaning of Paul's message:
1. fleshly (or carnal). Defined variously as "bodily," "temporal," "animal," or "unregenerate," the word appears three times in the first three verses to describe the Corinthians' actual spiritual condition, exactly contrary to their own self-perception as spiritually advanced and gifted. Elsewhere in 1 Cor. Paul contrasts "spiritual things" with "fleshly [carnal or material] things" in the morally neutral context of financial provision, alluding to the essential antonymy of the flesh and the Spirit (9:11). In Rom. 7:14 he uses the same term to refer to the most fundamental sort of aspirituality, in his general evaluation of corrupt, sinful human nature: "For we know that the law is spiritual, but I am carnal, sold into bondage to sin." Hebrews 7:16 gives the same sort of physical sense, in describing Christ as a high priest "according to the power of an endless life" rather than a "physical requirement" (NASB) or "fleshly commandment" (NKJV). So the sense of "fleshly" here is more like a natural or temporal condition common to all men than an overt or deliberate sinfulness.
2. master builder. This term is mentioned but once in the Bible, in v. 10, by Paul to describe his own foundation-laying apostolic ministry with a word-picture, that of an architect. Paul is careful to qualify himself here, adding that he functions in this role "according to the grace of God which was given to me," and that the foundation he builds upon is "none other" than Christ himself.
3. foundation. This is the core referent of Paul's discourse. The word refers to the substruction or underlying groundwork of a building. Paul claims the responsibility for laying the foundation (v. 10), and then immediately specifies that the foundation "which is laid," or "the one already laid" (NIV), is Jesus Christ (v. 11). In defining his ministry in paradoxical terms of laying a foundation already laid, Paul points up both the unique cutting-edge character of the apostolic calling and the eternally sufficient sacrifice of Christ superior to all the works of apostles and men combined. The ground-breaking, church-building mission of the apostles is that described by Paul again in Rom. 15:20: "to preach the gospel, not where Christ was not already named, so that I would not build on another man's foundation." While the sacrifice of Christ is complete, "already laid," the message of Christ has yet to penetrate every geographic region, so that the foundation of the church has yet to be laid in certain regions. This dual meaning of foundation is more or less repeated in Eph. 2:20-21, which describes "God's household, having been built on the foundation of the apostles and prophets, Christ Jesus Himself being the corner stone." The apostles are responsible for the founding, or foundation, of the church (by preaching and following Christ), but the ultimate foundation (corner stone) is still Christ Jesus. Perhaps it would help to clarify the distinction as that between (1) the foundation of the visible church on earth, the church-building work of the apostles; and (2) the foundation of faith (and thus the ultimate spiritual foundation of the church universal), Jesus Christ. (Rev. 21:14-23 offers a similar image, with the names of the twelve apostles on the foundation stones of the New Jerusalem, but with Christ as its temple, or spiritual center from which the light of heaven radiates.)
In 1 Tim. 2:19-20 he draws a word-picture strikingly similar to that of 1 Cor. 3, depicting the "foundation of God" (God or Christ himself), standing firm despite the lies of apostates and false teachers: "Nevertheless, the solid foundation of God stands..." Moreover, Paul alludes again to the quality of materials in building on the foundation of God: "But in a great house there are not only vessels of gold and silver, but also of wood and clay, some for honor and some for dishonor." In making the connection here between various building materials and honor (or sanctification, v. 21) and dishonor, he gives a clue as to what is meant by gold, silver, wood, hay, etc. Elsewhere in the NT, Jesus mentions foundations as the subject of a parable on obedience: One man is said to have "dug deep and laid a foundation on the rock," while another who heard the same message but did not act on it, is like a man "who built a house on the ground without any foundation" (Luke 6:46-49). Much as in Paul's metaphor in 1 Cor. 3, one man's work endured (while the other's was destroyed) as a direct consequence of properly building on the solid foundation, acting by faith on the message of Christ pertaining to himself.
4. work. As opposed to works, this term is used fairly consistently throughout the NT, often by Paul, in the singular to denote labor associated with a spiritual enterprise rather than as a false theological basis for salvation. Paul refers to the people of Corinth themselves as his "work in the Lord" (9:1), then speaks to them of the "work of the Lord" in 1 Cor. 15:8 and again in 16:10, the latter a reference to the missionary work of the apostles. Various uses within the genre of Pauline literature convey the basic thought of work done for Christ apart from, and in the established context of, salvation by faith. Paul's references to this sort of "work" (he uses the word no less than 19 times) indicate a number of shades of meaning: any legitimate work of ministry for the church, e.g., Philippians 2:30; activity associated with personal responsibility, Gal. 6:4; generally commendable behavior, 2 Thess. 2:17, 1 Tim. 5:10; pastoral ministry, 1 Tim.3:1; evangelistic ministry, 2 Tim. 4:5; behavior befitting a profession of faith, Titus 1:16; and submissive, congenial behavior, Titus 3:1-2. Though Paul uses this word more than any other NT writer, Jesus uses it to commend the act of the woman anointing him with oil at Bethany, Matt. 26:10; as well as to define the will of God, John 4:34; and significantly, he equates faith in God with "the work of God," in keeping with Paul's principle that works apart from faith are fruitless. Unlike works of the law, the work of faith will be rewarded: "If any man's work which he has built...remains, he will receive a reward" (v. 14). Within the NT, Hebrews reiterates this thought: "For God is not unjust to forget your work..." (Heb. 6:10). And the final words of Jesus recorded in the NT include an assurance that work will receive a due recompense: "Behold, I am coming quickly, and My reward is with Me, to give to every man according to his work (Rev. 22:12, NKJV).