labourers together with God = God's fellow-workers. The word "God" is in the genitive of possession (App-17), as in the two other clauses of the verse. It is the Figure of speech Anaphora (App-6), and the verse should read: "God's fellow-workers we are: God's husbandry, God's building, ye are. "Ministers are co-workers with one another, not with God, as though He were one of them. Were it so, "God" would be in the dative case.
labourers together with. Greek. sunergos. Occurs thirteen times. Three times as here, used generally; in all other cases used of individuals, Timothy, Titus, Luke, &c.
building. Greek. oikodome. Used in Mat_24:1. Mar_13:1, Mar_13:2; 2Co_5:1. Eph_2:21, of an edifice. Elsewhere twelve times of the act of building, and translated "edifying", in a metaphorical sense.