Matthew 6:6

ταμεῖον has high authority (אBDE) for ταμιεῖον; cp. the late form ὑγεία for ὑγίεια.

6. ταμιεῖον. A private oratory or place of prayer. These were usually in the upper part of the house; in classical Greek ‘storehouse’ or ‘treasury’, the meaning of the word Luke 12:24. See Matthew 24:26.

πρόσευξαι τῷ πατρί σου τῷ ἐν τῷ κρυπτῷ. Christ was the first to enjoin clearly secret and silent prayer. Certainly to pray aloud and in public appears to have been the Jewish practice (see however 1 Samuel 1:13); it is still the practice with the heathen and Mahommedans. The Roman looked with suspicion on private prayer: ‘quod scire hominem nolunt deo narrant’ (Seneca). Cp. Hor. Ep. I. 16. 59–62, where see Macleane’s note. Cp. also Soph. Electra 638, where Clytemnestra apologises for offering up a secret prayer.