2 Clement

Let us therefore serve God in a pure heart, and we shall be righteous; but if we serve Him not, because we believe not the promise of God, we shall be wretched.

Ἡμεῖς οὖν ἐν καθαρᾷ καρδίᾳ δουλεύσωμεν τῷ θεῷ, καὶ ἐσόμεθα δίκαιοι: ἐὰν δὲ μὴ δουλεύσωμεν διὰ τὸ μὴ πιστεύειν ἡμᾶς τῇ ἐπαγγελίᾳ τοῦ θεοῦ, ταλαίπωροι ἐσόμεθα.

For the word of prophecy also saith: Wretched are the double-minded, that doubt in their heart and say, These things we heard of old in the days of our fathers also, yet we have waited day after day and seen none of them.

λέγει γὰρ καὶ ὁ προφητικὸς λόγος: Ταλαίπωροί εἰσιν οἱ δίψυχοι, οἱ διστάζοντες τῇ καρδίᾳ, οἱ λέγοντες: Ταῦτα πάλαι ἠκούσαμεν καὶ ἐπὶ τῶν πατέρων ἡμῶν, ἡμεῖς δὲ ἡμέραν ἐξ ἡμέρας προσδεχόμενοι οὐδὲν τούτων ἑωράκαμεν.