Exegesis:

kai touto humin to sēmeion ‘and this for you the (or ‘a’) sign,’ with either estin ‘is’ (cf. Translator’s New Testament), or estai ‘will be’ (cf. An American Translation) understood, preferably the latter. touto ‘this’ points to the subsequent description of the sign; humin ‘for you,’ dative of advantage.

sēmeion ‘sign,’ ‘distinguishing mark,’ ‘miracle.’ Here the sign serves either to identify the new-born child or to prove the truth of what has been said about the child, but these interpretations do not exclude each other; the latter is preferable.

esparganōmenon kai keimenon en phatnē ‘wrapped up and lying in a manger,’ cf. on v. 7; strictly speaking only the second part of the phrase denotes something out of the ordinary and has therefore the character of a sign.

Translation:

This will be a sign for you, or, ‘this the you-will-recognize sign’ (Ekari), ‘by this you will recognize him’ (Leyden), following the first interpretation mentioned in Exegesis, or, “this will prove it to you” (An American Translation), following the other interpretation. For sign cf. also on 2.34.

Find. Receptor languages may distinguish between (1) ‘find/come-across’ (by chance), and (2) ‘find/obtain’ (as a result of deliberate seeking), as is the case here. In some languages one verb covers the concepts ‘to see’ and ‘to find’ (e.g. Tboli), or ‘to see,’ ‘to meet’ and ‘to find’ (e.g. Balinese).

A babe wrapped in swaddling cloths and lying in a manger. The verbs used are the same as in v. 7 but the aspect is different. This may be expressed by the use of different aspect forms, or by other means, compare e.g. ‘wrapped-him-up with/by-means-of swaddling-cloths,’ suggesting an act, in v. 7, with ‘wrapped-up in swaddling-cloths,’ suggesting repose, here (Bahasa Indonesia KB), ‘was wrapped by her in swaddling-cloths’ with ‘having-swaddling-cloths’ (Balinese), or, ‘put him in a manger’ with ‘lying in a manger’ (Sranan Tongo). In some languages a one-word rendering such as ‘wrapped-up’ or ‘swaddled’ is more idiomatic that a literal rendering of the phrase “wrapped up in swaddling cloths”. This may help to make it possible to recast the whole expression in such a way as to focus the attention on the second part, cf. ‘find a wrapped-up babe which was lying in a manger’ (cf. Batak Toba 1885). For babe cf. on v. 17.

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.