Exegesis:
poiēsate oun karpous axious tēs metanoias ‘then bear fruits that befit your repentance.’ oun is inferential and means ‘if you want to be saved, then….’ karpoi ‘fruits’ (a metaphor for erga ‘works,’ ‘deeds’) views the deeds as the outcome of some moral or inner force. The aorist tense of poiēsate expresses that a change of conduct or attitude is implied.
axios, of things, ‘corresponding,’ ‘consistent,’ of people, ‘worthy.’
kai mē arxēsthe legein en heautois ‘and do not begin to say to yourselves.’
archomai ‘to begin,’ but here it has lost this meaning and has no distinct semantic function, cf. on 4.21.
patera echomen ton Abraam ‘we have Abraham for our (fore) father.’ According to Jewish tradition Abraham’s merits could save Israel from the wrath of God, cf. Strack-Billerbeck I, 116-121.
legō … humin ‘I tell you.’ legō with following dative humin or soi serves as an emphatic introduction of a statement, which follows either in direct speech (e.g. in 6.27) or in indirect speech, connected by hoti (e.g. here).
dunatai ho theos ek tōn lithōn toutōn egeirai tekna tō Abraam ‘God is able from these stones to raise up children for Abraham’ ek tōn lithōn toutōn ‘from these stones’ depends upon egeirai but is not a genitive of place but of origin; the stones are, as it were, the material from which the children could be made.
Translation:
If the linguistic and the historical order should be parallel one may shift to, ‘change the mind so that the fruit/result may be seen’ (Ngäbere), ‘if you (really) repent, bear fruits that show so.’
Bear fruits that befit repentance. The metaphor, though nearly dead as such, should preferably be preserved here, because the formal tie between this verse and the next exists in the echoing of the phrase ‘bear fruits.’ — In Marathi one does not say ‘a tree bears fruit’ but the idiom is, ‘fruit comes to the tree’; in some other languages ‘to bear fruit’ is rendered by one verb, ‘to fruit,’ ‘to have-fruits.’ Such a verb or idiom can in some cases not go with an expression like ‘befit repentance’; then the translator may have to shift to a less obvious rendering, e.g. ‘produce fruits,’ ‘bring-to-light fruits.’ — That befit repentance, or ‘that agree with/show repentance,’ ‘that befit people who repent’ (Sranan Tongo), ‘that show you have repented.’
In some receptor languages, however, ‘bear fruits’ cannot be used in the required metaphorical sense, which has led several translators to the use of a non-metaphorical sense, rendering, e.g. ‘produce results.’ This, however, has the drawback of destroying the formal tie between vv. 8 and 9. In order to preserve that tie it may be preferable to make explicit the simile implied in ‘bear fruits,’ e.g. ‘just as fruit trees must bear fruit, so you must do things that will show that you have repented,’ or, ‘you are like fruit trees; the fruits you must bear are deeds that agree with your change of heart.’
Do not begin to say to yourselves (or, ‘in your heart/mind’), or ‘do not think’ (Kituba, Balinese); or, influenced by this specific context, ‘do not put-your-hope-in (the fact) that you…’ (Pohnpeian, similarly Manobo).
We have Abraham as our father, or ‘Abraham is our father.’ In the Greek such a genealogical claim can be expressed both in this form, starting from the father (cf. also John 8.39a) and in the reverse forms, starting from the children (cf. the next clause, and John 8.39b); in some other languages the reverse form is idiomatically to be preferred: ‘we belong to Abr.’s posterity/children,’ ‘we are descendants of Abr.’ (cf. Pohnpeian).
The phrase I tell you is sometimes parenthetical; in translation it may have to be given another position in the sentence. Its function is in some cases better rendered by some such word as ‘indeed,’ ‘certainly,’ cf. on 12.51.
God is able from these stones to raise up children to Abraham. One may have to change the structure of this clause, e.g. ‘God can use these stones to raise (or, to make./cause-to-exist/cause-to-be-born) children for Abr.,’ “God can take these rocks and make descendants for Abr.” (Good News Translation), ‘God can cause these stones to change-into Abr.’s children’ (Sranan Tongo). The emphasis is on “from these stones”; hence, ‘from, these very stones,’ “right out of these stones” (An American Translation). Semantically to Abraham serves in this context to qualify the children rather than to indicate the beneficiary of the process; hence some versions have ‘children of Abr.’ (Bahasa Indonesia, cf. also Phillips), cf. also, ‘children to-function-as offspring of Abr.’ (Javanese).
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.