The special endowment for his apostolic work. Compare Rom 1:5, grace and apostleship: Rom 12:3, Rom 12:6; Eph 3:7, Eph 3:8.
Wise (σοφὸς)
Skillful. See on Jam 3:13.
Master-builder (ἀρχιτέκτων)
Only here in the New Testament. “The architect does not work himself, but is the ruler of workmen” (Plato, “Statesman,” 259).
Foundation
The importance which Paul attached to the foundation was figured by the care employed in laying the foundation of the great Ephesian temple. “To avoid the danger of earthquakes, its foundations were built at vast cost on artificial foundations of skin and charcoal laid over the marsh” (Farrar).