1 Cor 3:5-17 uses an agricultural analogy and then seamlessly shifts to an architechural analogy. The parable of the field is that you are a field that belongs to God and Paul and Apollos are servants who work that field. The parable of the building is that you are the building, actually the Temple of God, (also then belonging to God) and Paul was the skilled master builder who laid the foundation of Jesus Christ and Apollos and others are workers who build on that foundation. Both parables make the same points, but the second one has the idea of accountabililty added to it because Paul tells us that the work that one does building on that foundation will be tested by fire. And those who built with the materials suitable for a Temple will have work that will survive and those who built with wood, hay and straw will see what they did go up in smoke. Both parables have the idea of a reward for one’s work — that reward we discover is the praise of God. And both parables then are an application of the theological foundation we have seen earlier in the letter to this problem of following particular personalities, forming parties, and spintering into competing groups.