To increase (προστίθημι prostithēmi)

And the Apostles said to the Lord, Increase our faith. (Ps 17:15)

Καὶ εἶπαν οἱ ἀπόστολοι τῷ κυρίῳ· πρόσθες ἡμῖν πίστιν.

Et dixerunt Apostoli Domino: Adauge nobis fidem.