Isocrates 1.27-28 (tr. George Norlin):
Set not your heart on the excessive acquisition of goods, but on a moderate enjoyment of what you have. Despise those who strain after riches, but are not able to use what they have; they are in like case with a man who, being but a wretched horseman, gets him a fine mount.  Try to make of money a thing to use as well as to possess; it is a thing of use to those who understand how to enjoy it, and a mere possession to those who are able only to acquire it. Prize the substance you have for two reasons—that you may have the means to meet a heavy loss and that you may go to the aid of a worthy friend when he is in distress; but for your life in general, cherish your possessions not in excess but in moderation.
ἀγάπα τῶν ὑπαρχόντων ἀγαθῶν μὴ τὴν ὑπερβάλλουσαν κτῆσιν ἀλλὰ τὴν μετρίαν ἀπόλαυσιν. καταφρόνει τῶν περὶ τὸν πλοῦτον σπουδαζόντων μέν, χρῆσθαι δὲ τοῖς ὑπάρχουσι μὴ δυναμένων· παραπλήσιον γὰρ οἱ τοιοῦτοι πάσχουσιν, ὥσπερ ἂν εἴ τις ἵππον κτήσαιτο καλὸν κακῶς ἱππεύειν ἐπιστάμενος.  πειρῶ τὸν πλοῦτον χρήματα καὶ κτήματα κατασκευάζειν. ἔστι δὲ χρήματα μὲν τοῖς ἀπολαύειν ἐπισταμένοις, κτήματα δὲ τοῖς κτᾶσθαι δυναμένοις. τίμα τὴν ὑπάρχουσαν οὐσίαν δυοῖν ἕνεκεν, τοῦ τε ζημίαν μεγάλην ἐκτῖσαι δύνασθαι, καὶ τοῦ φίλῳ σπουδαίῳ δυστυχοῦντι βοηθῆσαι· πρὸς δὲ τὸν ἄλλον βίον μηδὲν ὑπερβαλλόντως ἀλλὰ μετρίως αὐτὴν ἀγάπα.