Exegesis:
Vv. 29f may be viewed (a) as part of Jesus’ words describing the reactions to John’s preaching, or (b) as an inserted comment by Luke as to the various reactions to Jesus’ words. Though the decision is difficult, (a) appears to be the more probable view.
(V. 29) kai pas ho laos akousas kai hoi telōnai ‘and all the people who heard (him), and the tax collectors…,’ with John understood as the object of akousas. laos (cf. on 3.21) refers here to the common people as contrasted with the Pharisees and the scribes. kai hoi telōnai (cf. 3.12) is added as if on second thought, since akousas is in the singular; kai is ascensive, i.e. means ‘and even,’ cf. e.g. An American Translation.
edikaiōsan ton theon ‘acknowledged God, or God’s justice,’ cf. An American Translation. A rendering like “praised God” (New English Bible, cf. Translator’s New Testament) betrays a different interpretation of vv. 29ff.
dikaioō ‘to justify,’ ‘to treat as just,’ ‘to acknowledge as just.’
baptisthentes to baptisma Iōannou lit. ‘being baptized with the baptism of John,’ i.e. ‘being baptized by John’ (cf. 3.7, 16), to be understood as describing the way in which they acknowledged God (cf. An American Translation) or the result of it (cf. Phillips), preferably the former. baptisma (referring to the act of baptizing) is accusative of content.
(V. 30) hoi … Pharisaioi kai hoi nomikoi ‘the Pharisees and the experts in the law.’ For Pharisaioi cf. on 5.17.
nomikos ‘expert in the law,’ synonymous with nomodidaskalos (cf. on 5.17), and grammateus (cf. e.g. 5.21).
tēn boulēn tou theou ēthetēsan eis heautous ‘rejected the will of God with reference to themselves.’
boulē (also 23.51) ‘will,’ ‘purpose.’
atheteō ‘to nullify,’ hence ‘to reject,’ i.e. that which God wanted them to do, his will, or ‘to thwart,’ i.e. that which God had in mind to perpetrate, his purpose. The former is preferable. eis heautous is best understood as going with the clause as a whole.
mē baptisthentes hup’ autou ‘not being baptized by him,’ or preferably in the middle voice, ‘not having themselves baptized by him,’ hence “by refusing to be baptized by him” (An American Translation, cf. The Four Gospels – a New Translation, Phillips).
Translation:
On the basis of the interpretation preferred in Exegesis the following remarks have to be made.
For all the people cf. on 1.17, but for the people in contrast to its leaders some languages (e.g. in Indonesia) prefer a distinctive term, something like ‘the common people.’
The tax collectors, see on 3.12.
Heard this, preferably, ‘heard him/John, or his/John’s preaching/words.’
Justified God, or, more analytically, ‘acknowledged that God is just,’ cf. ‘gave God right’ (Sranan Tongo), ‘accepted the rightness of God by agreeing with it’ (Trukese, Pohnpeian); the Ekari rendering lit. means, ‘God is tremendous they thought.’
Having been baptized with the baptism of John, preferably, ‘having had themselves baptized with the baptism of J.,’ which may result in such rendering as, ‘having accepted/ taken baptism of J.’ (cf. An American Translation, Bible de Jérusalem, Marathi, Sranan Tongo, Javanese, Batak Toba), ‘having given themselves to be baptized by J.’ (Toraja-Sa’dan), ‘having asked J. to baptize them’; or, stressing John’s role, ‘they had themselves baptized by him—yes, by John himself’ (Cuyono). Cf. also on 3.7 and 3. The descriptive connexion with the main clause is usually better made explicit, e.g. ‘by having (or, when they) had themselves baptized…,’ or, changing the clause order, .’.. had taken John’s baptism. By this means they justified…’ (cf. Marathi).
(V. 30) Lawyer, i.e. ‘expert/scholar of the law,’ ‘one who knows/studies/interprets the law,’ ‘one who knows the commandments’ (Uab Meto), ‘man of commandments’ (East Nyanja, Lomwe, Yao). The rendering may have to coincide with that of “scribe” (see 5.21) and/or “teacher of the law” (see on 5.17). For ‘law’ cf. on 2.22.
Rejected … for themselves, or ‘concerning themselves.’ Some descriptive renderings are, ‘declared that … was not valid for themselves,’ ‘showed that they did not reckon with…,’ ‘in their hearts they had no use for…’ (Tzeltal), ‘waved, putting at the side…’ (Sranan Tongo).
The purpose of God, or ‘what God wanted them to do,’ ‘the way God would-fain have them follow’ (Tboli); or, ‘God’s will’ (see on 12.47).
If the translator prefers to take these verse as a comment made by Luke (see e.g. Revised Standard Version), this choice will influence some details of his
Translation: the tense of ‘heard,’ ‘justified,’ ‘rejected’ may have to be different, because the reference is to the near past; the object to be understood with ‘heard’ is ‘Jesus,’ ‘Jesus’ words’ (i.e. vv. 24ff); the participial phrases express reason not means; the shift from direct to indirect discourse after v. 28 and the reverse one after v. 30 may be indicated by some such device as brackets, or, preferably, by inserting ‘thus he/Jesus said’ after the former, and/or. ‘then he/Jesus spoke again’ after the latter verse.
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.