Exegesis:

kai egeneto ‘and it happened,’ cf. on 1.8.

en mia tōn hēmerōn ‘one day,’ cf. on 5.17.

didaskontos autou ton laon en tō hierō kai euaggelizomenou ‘while he was teaching the people in the temple and preaching the good news.’ Both teaching and preaching have the good news of the kingdom of God as content, the difference being that with teaching the emphasis is on explaining and understanding, and with preaching on appeal and acceptance. For en tō hierō cf. on 2.27.

epestēsan hoi archiereis kai hoi grammateis ‘the chief priests and the experts of the law came up.’ For ephistamai cf. on 2.9; for hoi archiereis cf. on 9.22; for grammateis cf. on 5.21.

sun tois presbuterois ‘together with the elders,’ virtually equivalent to kai hoi presbuteroi. For presbuteros cf. on 7.3.

Translation:

The verse may better be divided into two sentences, e.g. ‘One day he was … gospel; then (or, as he was doing so) the chief priests … came up.’ For preaching the gospel, or, “telling them the good news” (New English Bible), see on 3.18; for the elders see on 7.3.

Came up, or, ‘came to stand by/around him,’ i.e. joined the audience.

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.