Be not swept off your feet by the vividness of the impression, but say, "Impression, wait for me a little. Let me see what you are and what you represent. Let me try you."
τὸ πρῶτον δ᾿ ὑπὸ τῆς ὀξύτητος μὴ συναρπασθῇς, ἀλλ᾿ εἰπὲ 'ἔκδεξαί με μικρόν, φαντασία· ἄφες ἴδω τίς εἶ καὶ περὶ τίνος, ἄφες σε δοκιμάσω.'
Original text (Ancient Greek)
Notes from Wikiquote
Reported in Bartlett's Quotations (1919) as "Be not hurried away by excitement, but say, "Semblance, wait for me a little".