Justin Martyr, Dialogue with Trypho

“Learn, therefore, to keep the true fast of God, as Isaiah says, that you may please God. Isaiah has cried thus: ‘Shout vehemently, and do not spare: lift up thy voice as with a trumpet, and show My people their transgressions, and the house of Jacob their sins. They seek Me from day to day, and desire to know My ways, as a nation that did righteousness, and forsook not the judgment of God. They ask of Me now righteous judgment, and desire to draw near to God, saying, Wherefore have we fasted, and Thou seest not? and afflicted our souls, and Thou hast not known? Because in the days of your fasting you find your own pleasure, and oppress all those who are subject to you. Behold, ye fast for strifes and debates, and smite the humble with your fists. Why do ye fast for Me, as to-day, so that your voice is heard aloud? This is not the fast which I have chosen, the day in which a man shall afflict his soul. And not even if you bend your neck like a ring, or clothe yourself in sackcloth and ashes, shall you call this a fast, and a day acceptable to the Lord. This is not the fast which I have chosen, saith the Lord; but loose every unrighteous bond, dissolve the terms of wrongous covenants, let the oppressed go free, and avoid every iniquitous contract. Deal thy bread to the hungry, and lead the homeless poor under thy dwelling; if thou seest the naked, clothe him; and do not hide thyself from thine own flesh. Then shall thy light break forth as the morning, and thy garments33 ἱμάτια; some read ἰάματα, as in LXX., “thy health,” the better reading probably. shall rise up quickly: and thy righteousness shall go before thee, and the glory of God shall envelope thee. Then shalt thou cry, and the Lord shall hear thee: while thou art speaking, He will say, Behold, I am here. And if thou take away from thee the yoke, and the stretching out of the hand, and the word of murmuring; and shalt give heartily thy bread to the hungry, and shalt satisfy the afflicted soul; then shall thy light arise in the darkness, and thy darkness shall be as the noon-day: and thy God shall be with thee continually, and thou shalt be satisfied according as thy soul desireth, and thy bones shall become fat, and shall be as a watered garden, and as a fountain of water, or as a land where water fails not.’34 Isa. lviii. 1–12. ‘Circumcise, therefore, the foreskin of your heart,’ as the words of God in all these passages demand.”

[15] Καὶ τὴν ἀληθινὴν οὖν τοῦ θεοῦ νηστείαν μάθετε νηστεύειν, ὡς Ἠσαίας φησίν, ἵνα τῷ θεῷ εὐαρεστῆτε. κέκραγε δὲ Ἠσαίας οὕτως: Ἀναβόησον ἐν ἰσχύϊ καὶ μὴ φείσῃ, ὡς σάλπιγγι ὕψωσον τὴν φωνήν σου καὶ ἀνάγγειλον τῷ γένει μου τὰ ἁμαρτήματα αὐτῶν καὶ τῷ οἴκῳ Ἰακὼβ τὰς ἀνομίας αὐτῶν. ἐμὲ ἡμέραν ἐξ ἡμέρας ζητοῦσι καὶ γνῶναι τὰς ὁδούς μου ἐπιθυμοῦσιν, ὡς λαὸς δικαιοσύνην πεποιηκὼς καὶ κρίσιν θεοῦ οὐκ ἐγκαταλελοιπώς. αἰτοῦσί με νῦν κρίσιν δικαίαν καὶ ἐγγίζειν θεῷ ἐπιθυμοῦσι, λέγοντες: Τί ὅτι ἐνηστεύσαμεν καὶ οὐκ εἶδες, ἐταπεινώσαμεν τὰς ψυχὰς ἡμῶν καὶ οὐκ ἔγνως; ἐν γὰρ ταῖς ἡμέραις τῶν νηστειῶν ὑμῶν εὑρίσκετε τὰ θελήματα ὑμῶν, καὶ πάντας τοὺς ὑποχειρίους ὑμῶν ὑπονύσσετε: ἰδοὺ εἰς κρίσεις καὶ μάχας νηστεύετε, καὶ τύπτετε πυγμαῖς ταπεινόν. ἵνα τί μοι νηστεύετε ἕως σήμερον, ἀκουσθῆναι ἐν κραυγῇ τὴν φωνὴν ὑμῶν; οὐ ταύτην τὴν νηστείαν ἐγὼ ἐξελεξάμην, καὶ ἡμέραν ταπεινοῦν ἄνθρωπον τὴν ψυχὴν αὐτοῦ: οὐδ' ἂν κάμψῃς ὡς κρίκον τὸν τράχηλόν σου καὶ σάκκον καὶ σποδὸν ὑποστρώσῃ, οὐδ' οὕτως καλέσετε νηστείαν καὶ ἡμέραν δεκτὴν τῷ κυρίῳ. οὐχὶ τοιαύτην νηστείαν ἐγὼ ἐξελεξάμην, λέγει κύριος: ἀλλὰ λύε πάντα σύνδεσμον ἀδικίας, διάλυε στραγγαλιὰς βιαίων συναλλαγμάτων, ἀπόστελλε τεθραυσμένους ἐν ἀφέσει καὶ πᾶσαν συγγραφὴν ἄδικον διάσπα. διάθρυπτε πεινῶντι τὸν ἄρτον σου καὶ πτωχοὺς ἀστέγους εἰσάγαγε εἰς τὸν οἶκόν σου: ἐὰν ἴδῃς γυμνόν, περίβαλλε, καὶ ἀπὸ τῶν οἰκείων τοῦ σπέρματός σου οὐχ ὑπερόψει. τότε ῥαγήσεται πρώϊμον τὸ φῶς σου, καὶ τὰ ἱμάτιά σου ταχὺ ἀνατελεῖ, καὶ προπορεύσεται ἔμπροσθέν σου ἡ δικαιοσύνη σου, καὶ ἡ δόξα τοῦ θεοῦ περιστελεῖ σε. τότε βοήσῃ, καὶ ὁ θεὸς εἰσακούσεταί σου: ἔτι λαλοῦντός σου ἐρεῖ: Ἰδοὺ πάρειμι. ἐὰν δὲ ἀφέλῃς ἀπὸ σοῦ σύνδεσμον καὶ χειροτονίαν καὶ ῥῆμα γογγυσμοῦ, καὶ διδῷς πεινῶντι τὸν ἄρτον σου ἐκ ψυχῆς, καὶ ψυχὴν τεταπεινωμένην ἐμπλήσῃς, τότε ἀνατελεῖ ἐν τῷ σκότει τὸ φῶς σου, καὶ τὸ σκότος σου ὡς μεσημβρία, καὶ ἔσται ὁ θεός σου μετὰ σοῦ διὰ παντός, καὶ ἐμπλησθήσῃ καθὰ ἐπιθυμεῖ ἡ ψυχή σου, καὶ τὰ ὀστᾶ σου πιανθήσονται, καὶ ἔσται ὡς κῆπος μεθύων καὶ πηγὴ ὕδατος ἢ γῆ ᾗ μὴ ἐξέλιπεν ὕδωρ. περιτέμεσθε οὖν τὴν ἀκροβυστίαν τῆς καρδίας ὑμῶν, ὡς οἱ λόγοι τοῦ θεοῦ διὰ πάντων τούτων τῶν λόγων ἀξιοῦσι.