Exegesis:

plēn ‘yet,’ i.e. ‘though you have this authority.’

en toutō mē chairete hoti… ‘do not rejoice over the fact that….’

hoti ta onomata humōn eggegraptai en tois ouranois ‘that your names have been enrolled in heaven,’ i.e. you are members of the heavenly community. For the background of this clause see commentaries, especially Plummer.

eggraphō ‘to write,’ ‘to record,’ ‘to enroll.’

Translation:

Formally the two clauses are imperatives, expressing a negative and a positive command, but semantically they form a statement expressing preference; hence a rendering such as, ‘you should, or may, not so much rejoice in that…, but rather you should/may rejoice in that….’ Further adjustments that may be necessary are: putting the positive clause first; using the verb only once (cf. New English Bible); or shifting to a conditional or concessive construction, e.g. ‘if you rejoice, rejoice (or, do so) not so much in this, that…, but rather in that…,’ ‘you may rejoice, but rather because your names … than because the spirits….’

For spirits see on 9.39 and references.

Your names are written in heaven, or, ‘are enrolled in the book of heaven’ (Kele). The expression to be used should fit the way membership of a social group is recorded in the culture. The plural is distributive; the implied agent is God.

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.