Exegesis:

kagō humin legō ‘and I tell you’ (cf. on 3.8), indicating that the inferences will be drawn from vv. 5-8, cf. 16.9.

aiteite, kai dothēsetai humin ‘ask and (it) will be given to you.’ aiteite is best understood as referring to prayer. The object of aiteite is not indicated, nor the subject of dothēsetai. The agent of dothēsetai is God, and the nature of what is sought and given is indicated by pneuma hagion in v. 13.

zēteite, kai heurēsete ‘seek and you shall find,’ again without indication of the object.

krouete, kai anoigēsetai humin ‘knock and (the door) will be opened to you.’ For this picture cf. 13.24f, where the entrance into the kingdom of God is referred to.

krouō ‘to knock at the door.’

Translation:

Ask. If an object has to be added, one may use, ‘what you need.’

It will be given you, or, ‘you will receive it,’ ‘God will give you what you ask.’

Seek. For an object, if required again, see above.

You will find, cf. on 2.12. Add, if necessary, ‘it,’ or, ‘what you seek.’

Knock and it will be opened to you, or, ‘knock at the door and it will be opened to you,’ or, ‘knock and the door will open to you, or, God will open the door for you.’ Where it is not customary to ask admittance by knocking, one may have to use ‘call’ (some Mexican languages, and Zanaki), ‘speak’ (Tzeltal), ‘clap’ (Zarma), the normal terms for announcing one’s arrival. The use of ‘entrance/doorway’ for ‘door’ may entail the use of ‘to allow to enter’ instead of to open. Cf. also on 12.36.

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.