Exegesis:

egō de ‘but I…,’ contrasting with humas.

edeēthēn peri sou ‘I have prayed for you.’ For deomai cf. on 5.12. peri sou lit. ‘with regard to you,’ hence, ‘for you.’

hina mē eklipē hē pistis sou ‘that your faith may not fail.’ For ekleipō cf. on 16.9.

kai su ‘and you (on your part),’ contrasting with egō. It should be noted that Simon is here singled out from the disciples addressed in humas, because he will receive a special commission with regard to the others.

pote epistrepsas ‘when once you have turned back,’ scil. ‘to me,’ after having been sifted by Satan. pote refers to an undefined moment in the future. For epistrephō cf. on 1.16. Here it is intransitive.

stērison tous adelphous sou ‘strengthen your brothers,’ i.e. your fellow-disciples. stērizō (cf. on 9.51) is used here in the figurative sense of strengthening somebody’s faith, or, courage.

Translation:

I have prayed for you. For the verb see on 1.10. The reference is probably to something that happened on the day of speaking; in a language like Foe, therefore, one would use the near past tense. To bring out that you is singular one may say, “for you, Simon” (The Four Gospels – a New Translation, Good News Translation).

That your faith may not fail, or, ‘that you do not stop (or, that you persevere/persist in) believing (in me).’ Fail has also been rendered in this context by ‘collapse’ (Balinese), ‘disappear’ (Tae’), ‘be-extinguished’ (Batak Toba).

Strengthen, or, ‘make strong/firm,’ or marking the figurative meaning, ‘make-strong the heart/mind of’ (Tae,’ Batak Toba).

Brethren, see on “brother” in 6.41.

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.