Exegesis:

legō humin ‘I tell you,’ cf. on 3.8. Subject of legō is Jesus (as e.g. in 18.8 in a similar context), or the king of the parable (cf. v. 27). The latter is preferable.

panti tō echonti dothēsetai ‘to every one who has will (more) be given,’ cf. 8.18. The clause brings the application of the parable into the context of the kingdom of God. The object of echonti and the subject of dothēsetai is best understood as the fruit of obedience to God.

apo de tou mē echontos kai ho echei arthēsetai ‘from him who has not, even what he has will be taken away,’ paradoxical statement, describing the opposite of the preceding clause, cf. 8.18, where instead of ho echei it reads ho dokei echein ‘what he thinks he has.’

Translation:

For the two clauses see on the less paradoxically worded passage in 8.18.

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.