Exegesis:

kai idou ‘and behold,’ cf. on 1.20.

eisin eschatoi hoi esontai prōtoi ‘some are (now) last who will be first,’ i.e. when the kingdom comes. The clause refers to the people of v. 29.

eisin prōtoi hoi esontai eschatoi ‘some are (now) first who will be last.’ The people referred to are the Jews whom Jesus addresses.

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.