Exegesis:

ērate tēn kleida tēs gnēseōs ‘you have taken away the key to knowledge.’ airō means here ‘to take away from its proper place, so that it cannot be used’ (cf. 8.12). The phrase kleis tēs gnōseōs is best understood metaphorically as the key that opens the way to the understanding of Scripture which is the way of salvation (cf. gnōsis sōtērias ‘knowledge of salvation,’ 1.77). The experts in the law have a wrong interpretation of the Old Testament and this makes it impossible for them to find salvation. kleis.

autoi ouk eisēlthate ‘(consequently) you have not gone in yourselves,’ scil. into the knowledge of salvation. This metaphorical use of eiserchomai (cf. also 22.40, 46, Mt. 25.21) is a Hebraism. The asyndeton indicates that this clause, and also the next one, are the result of the taking away of the key.

tous eiserchomenous ekōlusate ‘those who wanted to enter you have stopped.’ The participle tous eiserchomenous is best understood as conative. For kōluō cf. on 6.29.

Translation:

The key of knowledge, preferably, “the key to (the door of) knowledge” (The Four Gospels – a New Translation, An American Translation), “the key that opens the door to the house of knowledge” (Good News Translation). The function of key may have to be described, e.g. ‘unlocker’ (East Nyanja, Yao), ‘means to open,’ ‘what opens the way to,’ and knowledge, or, ‘house of knowledge’ may have to be explained, e.g. ‘the place where people can acquire knowledge, or, can learn to understand the Scriptures.’

Hindered, or, “kept out” (An American Translation), ‘stopped’ (Shona 1963), ‘did not allow’ (Tzeltal).

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.