Exegesis:

gegraptai hoti ‘it is written (that),’ introduces a quotation from the Old Testament, cf. on 3.4.

ouk ep’ artō monō zēsetai ho anthrōpos ‘not on bread alone shall man live,’ i.e. there are other things which are as important as bread for man. In the light of Jn. 4.34 it seems probable that Jesus here implicitly refers to obedience to God as being as important for man’s life as bread. In ep’ artō monō ‘on bread alone,’ epi with dative indicates that on which life is based.

zēsetai ‘shall live,’ has the force of a command.

ho anthrōpos ‘man,’ in English without article as a categorical indication; in other western languages the definite article is required in this meaning. The phrase is an implicit reply to the supposition of the devil ‘if you are the Son of God’: Jesus declines the challenge to prove that he is the Son of God but ranks himself with man. This is no denial of his sonship as such but a refusal to use its prerogatives in order to satisfy his human needs.

Translation:

It is written, cf. on 2.23. A reference to the book may be required here, cf. ‘in the Book of God it says’ (Toraja-Sa’dan), ‘it is written in the Scriptures’ (Marathi).

Man shall not live by (or, on) bread alone. The sentence structure often has to be recast, cf. ‘man’s life is not by-means-of bread only’ (Javanese), ‘bread alone cannot make people live’ (Sranan Tongo), ‘it is not just bread that people live by’ (Pohnpeian, similarly Tae’), ‘as though food (lit. what-is-eaten) only the life of man!’ (Batak Toba). For alone, or, ‘without anything else than.’

Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.