Exegesis:

ouchi tauta edei pathein ton Christon ‘was it not necessary that the Messiah should suffer these things?’ For ouchi cf. on 4.22. For edei and for the idea which the clause expresses cf. on 9.22. For ho Christos cf. on 2.11, 26.

kai eiselthein eis tēn doxan autou ‘and to enter into his glory,’ syntactically also dependent upon edei but semantically of a different nature. It may be taken in a final sense, ‘in order to enter,’ in a temporal sense, ‘before entering,’ or in a consecutive sense, ‘and so to enter.’ The last is preferable. The phrase eiselthein eis (to be understood primarily in a spatial sense, as doxa denotes the heavenly realm of glory) means ‘to come into,’ hence, ‘to come to share in,’ ‘to come to enjoy.’

Translation:

Was it not necessary that the Christ should suffer, rhetorical question anticipating an affirmative answer; hence, as a statement, e.g. ‘it certainly was (or, you should know that it was) necessary that….’ For to be necessary, indicating divine necessity, cf. on “must” in 2.49, for the Christ see on 2.11, and for to suffer on 9.22.

Enter into his glory, or, ‘so to come to enjoy his glory,’ ‘thus He would begin to be considered great/honoured’ (Tzeltal). For glory see references on 2.9.

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.