3:4 Paul … Apollos. Factionalism was the divisive product of carnality. Cf. 1:11–13. †

3:5–7 What then is Apollos … Paul? A humble, but accurate assessment of the roles that ministers play. the Lord gave … God who causes the growth. It is the Lord alone who can give the faith to the spiritually ignorant and dead. Salvation is God’s work of grace to whom He chooses to give it (see notes on Ro 9:15–19; Eph 2:8, 9).

3:8 are one. All the human instruments God uses to produce salvation life are equally considered and rewarded for their willingness to be used by God. But all the glory goes to Him, who alone saves. Because of that, the silly favoritism of v. 4; 1:12 is condemned. See notes on Mt 20:1–16.

3:9 we. Paul, Apollos, Peter, and all ministers are equal workers in the field, but the spiritual life from that field is entirely by God’s grace and power. God’s building. Paul shifts the imagery from agricultural to construction (vv. 10–17). †

3:10 master builder … foundation. The Gr. word is the root for architect, but contained the idea of builder as well as designer. Paul’s specialty was designing and building spiritual foundations (cf. Ro 15:20). He was used by God to establish the groundwork for churches in Asia Minor, Macedonia, and Greece. Others (e.g., Timothy, Apollos) built the churches up from his foundations. That God used him in that way was all of grace (cf. v. 7; 15:20; Ro 15:18; Eph 3:7, 8; Col 1:29). each man. This primarily refers to evangelists and pastor-teachers.

3:11 no … foundation other than. Paul did not design the foundation, he only laid it down by preaching Christ. Cf. 1Pe 2:6–8.