BROTHERS and SISTERS, we are God’s co-workers, and you are God’s field, God’s building. According to the grace of God given to me, like a skilled master builder, I have laid a foundation, and someone else is building on it. Each builder must choose with care how to build on it. For no one can lay any foundation other than the one that has been laid – and that foundation is Jesus Christ. Now if anyone builds on the foundation with gold, silver, precious stones, wood, hay, straw – the work of each builder will be revealed. For the Day will disclose it, because it will be revealed with fire, and the fire will test what sort of work each has done. If what has been built on the foundation survives, the builder will receive a reward. If the work is burned up, it will be lost, but the builder will be saved, but only as through fire. Do you not know that you are the temple of God, and that God’s Spirit dwells in you? If anyone destroys the temple of God, God will destroy that person. For the temple of God is holy, and you are that temple.
Saint John Chrysostom explains what it means to be "God's co-workers,"
Paul's assertion that they are one, refers to their inability to do anything without God Who gives the increase. Since this had a tendency to make people more careless - I mean all being esteemed as one - whether they had labored much or little, observe how he sets this right. He says, "Each will receive their own reward according to their own labor." Do you see how to them he has also assigned no small task, having before laid down that the whole is of God? For the field is not called the farmer's, but the householder's. Again, the building is not the workman's, but the master's.
The Whole Counsel of God Bible study: