Exegesis:

egeneto de … diaporeuesthai auton dia sporimōn ‘and it happened that he was passing through grainfields.’ In this form the egeneto-construction (cf. on 1.8) relates the introductory circumstances.

diaporeuomai ‘to go, or, to walk through.’

sporima, plural, ‘standing grain,’ ‘grainfields.’

kai etillon hoi mathētai autou ‘and his disciples were plucking,’ i.e. tous stachuas ‘the heads of grain.’ The imperfect tense indicates repeated action. tillō.

kai ēsthion tous stachuas psōchontes tais chersin ‘and were eating the heads of grain, rubbing them with their hands.’ Strictly speaking the rubbing comes before the eating but in a general sense both acts happen simultaneously. psōchō.

Translation:

While he was going through … Actually the agents are Jesus and his disciples; hence ‘Jesus and his disciples walked in the midst of’ (Tae’ 1933), or in honorific languages, to avoid double translation of the verb, ‘while Jesus, accompanied by his disciples, was going through…,’ or with a further change, ‘while the disciples, followed Jesus through…, they….’ Going through, or, to bring out that he was not treading the grain under foot, ‘taking his way through,’ ‘walked between’ (Pohnpeian), ‘going along a path through’ (Amganad Ifugao).

Grainfields, or, ‘cultivated-fields’ (Shona 1966), ‘fields’ (Marathi). For “grain” in the sense used here see on “wheat” in 3.17.

Plucked and ate some ears of grain, rubbing them in their hands. It is usually better to take the noun object with the first verb, and to change the order of the second and third verb, cf. e.g. “pick the heads of wheat, rub them in their hands, and eat the grain” (Good News Translation), or with a final construction, .’.. they rubbed it in their hands, to chew on’ (Tboli). When another cereal is chosen to render ‘wheat’ details will have to be adjusted to fit its characteristics and the more or less specific terms used with reference to it. In some cases the verb ‘to pluck/pick’ does not take ‘ears of grain’ as object, but ‘the grains,’ or the name of he plant itself, as in Toraja-Sa’dan, Balinese, Tzeltal, Trukese. Then “rubbing” has to be taken in the sense of removing the husks of the grains. For ears of grain; some substitutes used are, ‘corn cobs’ (Kele), ‘fruits of the rice’ (Tboli). For ate some languages use a more specific term here, e.g. ‘chewed/nibbled-on-rice-kernels’ (Tboli, which possesses still another term for chewing on kernels of corn).

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.