Natalio Fernandez Marcos, author of The Septuagint in Context, says, “Nowhere in the New Testament is the need for a Semitic Vorlage demanded by the evidence, and most of the Hebraisms invoked by philologists are more easily explained as indirect Hebraisms or Septuagintalisms through the sub-language that was created for the Scriptures by the translations of the Bible in Greek” (Septuagint, 333).
In my study of Greek Job, I have come across at least two examples of the use of προσθείς + finite verb which translates Hebrew יסף + infinitive, “to X again”, in which the action to be repeated is carried by the infinitive. In Job 27:1 and 29:1, Job takes up his parable/discourse again. The OG renders this construction as προσθείς + εἶπεν: lit. having added/furthered, Job said… Or “Again, he spoke his discourse.” LSJ lists this meaning for προστίθημι only for LXX and NT. A simple example from the NT comes from Luke 19:11: Ἀκουόντων δὲ αὐτῶν ταῦτα προσθεὶς εἶπεν παραβολὴν, “Now after hearing these things, he again spoke a parable…”
Since there is some debate over whence this NT construction comes (Hebrew or Aramaic Vorlage or LXX influence), it is interesting to compare it to Aquila’s revision of Job 27:1: καὶ προσέθηκεν Ἰὼβ ἆραι τὴν παραβολὴν αὐτοῦ καὶ εἶπε (lit. And he added Job to take up his parable and he said). Predictably, Aquila renders every word of his Hebrew source into Greek, even preserving the exact Hebrew word order. He has translated the Hebrew verb ultra literally, which preserves the Hebrew parataxis, whereas the OG translator created a hypotactic construction. Nowhere do the NT authors use the construction of Aquila to my knowledge, but they do use the construction of the LXX with some frequency.
This observation and the phenomenon of Septuagintalisms in general (see the list in Marcos on pages 333-35) indicate probably that the NT authors were influenced by the LXX and perhaps in some cases the early revisers, but might it also indicate that they did not have much recourse, if any, to a Hebrew parent text and that they were not very influenced by its linguistic makeup? If they had recourse to the Hebrew parent text of the Greek OT, would we expect more literal renderings such as we find in Aquila or Theodotion, who clearly had such an access? Of course there are more angles to this discussion, which I have left out (e.g. revision of the OG by the time of the NT, what was the exact form of the Greek OT during the first century AD? etc.). All I’m asking at this time is, do the presence of Septuagintalisms add to the growing consensus that the NT authors were more, if not exclusively, influenced by the LXX than the Hebrew text and therefore they may not have made ad hoc renderings from this text?
[Caveat: Text form does not indicate a different canon thus the NT authors' dependence on the LXX does not mean that they were thinking in terms of the so called "wider canon" of the LXX. That such a conception existed at all is dubious according to a thorough examination of all of the evidence.]