Exegesis:

ouch heurethēsan hupostrepsantes … ei mē ho allogenēs houtos lit. ‘were there found none returning … except this foreigner?’ The clause is best understood as a question. heuriskomai with adjective or participle means ‘to be found’ in the sense of ‘to appear’; that which appears is expressed by the adjective or participle, cf. The Four Gospels – a New Translation and Plummer.

allogenēs ‘foreigner’ in the sense of ‘non-Israelite.’

dounai doxan tō theō ‘in order to give praise to God,’ final infinitive; the phrase is equivalent to doxazō with accusative.

Translation:

The force of this question is sometimes brought out by the use of introductory phrases such as, ‘is it really so that…,’ “can it be true that…” (The Four Gospels – a New Translation).

Was … found, or, ‘did appear,’ ‘was-seen’ (Toraja-Sa’dan), often simply ‘was there.’

No one … except this foreigner. Adjustments in the line of the notes on 8.51 and 10.22 may lead here to something like, ‘is there no other who returns and gives … than this foreigner’ (Tae’), ‘is this foreigner the only one to come back and give…’; or in two clauses, e.g. ‘This foreigner here comes back and gives … Why could the others (or, the nine) not come also?,’ or, ‘Does this one who is not an Israelite return and give…, but do the Israelites not do so, or, not come back to do so?.’ Foreigner, or, ‘man-from-outside’ (Sranan Tongo, Bahasa Indonesia), ‘man from another people’ (Javanese), ‘man who is not of our (inclus.) people (Tae’ 1933), or, not of (the people) Israel.’

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.