Exegesis:

kai su de, paidion ‘and you, child.’ These words introduce the second part of Zechariah’s prophecy, in which he addresses the child directly and speaks about his mission in the service of the Lord. The two connectives kai and de have different function: kai expresses the idea of continuation; John’s ministry is not to be separated from the Messianic prophecies of vv. 68-75; de however marks the transition from the more general part of Zechariah’s prophetic hymn to the part referring specifically to the child whose birth was the occasion for the hymn.

paidion ‘child,’ see on v. 59.

prophētēs hupsistou klēthēsē ‘prophet of the Most High you will be called,’ cf. on vv. 32 and 70.

proporeusē gar enōpion kuriou ‘for you will go before the Lord’; this will be his mission as a prophet, in fulfilment of what Gabriel had said to Zechariah, and of the prophecy of Mal. 3.1, quoted in the next phrase.

proporeuomai ‘to go before somebody,’ equivalent to proerchomai in v. 17.

enōpion kuriou ‘before the Lord,’ i.e. as his forerunner, cf. on v. 17.

hetoimasai hodous autou ‘to make ready his ways’; for hetoimazō cf. on v. 17; here it means to bring into readiness the existing but impassable roads; the genitive autou suggests here primarily that the Lord himself will come along them.

Translation:

For child see on v. 7, for the Most High on v. 32.

Will be called. The agent is ‘God’ rather than ‘people.’

To prepare his ways. To make clear the function of the pronoun here it may be preferable to say, ‘the way (along which) he will come,’ ‘the way on-which-his-treading’ (Javanese), or to change the syntactic pattern of the phrase, e.g. ‘to prepare for-him the ways’ (Bible de Jérusalem).

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.