Exegesis:
idōn de ho hekatontarchēs to genomenon ‘when the centurion saw what had happened.’ For ho hekatontarchēs cf. on 7.2. The article ho does not refer to a previous mention of the centurion but depicts him as the man who was naturally supposed to preside over the execution. to genomenon refers to all events and circumstances of Jesus’ death, cf. Plummer.
edoxazen ton theon legōn ‘he praised God (by) saying…’; it implies that he praised God unwittingly, cf. Plummer. For doxazō cf. on 2.20.
ontōs (also 24.34) ‘really,’ ‘certainly.’
ho anthrōpos houtos dikaios ēn ‘this man was righteous.’ dikaios is used either in a judicial sense (‘innocent’), or in a moral sense (‘good’), preferably the latter.
Translation:
The centurion, see on 7.2. The force of the definite article may lead to a rendering such as ‘the commander (of the soldiers) present there.’
For what had taken place cf. on “thing that has happened” in 2.15; for “praised” on 2.13.
Certainly, cf. on 22.59. The word characterizes the centurion’s words as an affirmation of the good reports he had heard previously about Jesus.
Innocent, preferably, ‘(a) good/honest/upright (man)’; see also references on 1.6.
tuptontes ta stēthē hupestrephon ‘went home beating their breasts.’ The imperfect tense is durative and suggests that they left the place slowly. For the phrase tuptontes ta stēthē cf. on 18.13.
Translation:
If partial co-ordination is preferable one may shift e.g. to, ‘very many people had gathered (there) to see the sight; after they had seen what had taken place, they returned home beating (or, and on their way they beat) their breast.’
To see the sight, or, “to watch the spectacle” (Good News Translation). Several languages (e.g. Javanese, Batak Toba) possess one specific verb for ‘to see/gaze-at a spectacle/performance.’
Beating their breasts, see on 18.13; the plural is distributive.
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.