While I am still reading, and I am no where near ready to put anything more into writing than I have already done, I thought it would be interesting if if I shared the following excerpt I found in Barnes commentary regarding Ephesians 2:8. The verse itself reads:
Eph 2:8 For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:
And I think that the ESV in this instance has something interesting to add:
Eph 2:8 ESV For by grace you have been saved through faith. And this is not your own doing; it is the gift of God,
And Barnes' notes on the last phrases:
And that not of yourselves - That is, salvation does not proceed from yourselves. The word rendered “that” - τοῦτο touto - is in the neuter gender, and the word “faith” - πίστις pistis - is in the feminine. The word “that,” therefore, does not refer particularly to faith, as being the gift of God, but to “the salvation by grace” of which he had been speaking. This is the interpretation of the passage which is the most obvious, and which is now generally conceded to be the true one; see Bloomfield. Many critics, however, as Doddridge, Beza, Piscator, and Chrysostom, maintain that the word “that” (τοῦτο touto) refers to “faith” (πίστις pistis); and Doddridge maintains that such a use is common in the New Testament. As a matter of grammar this opinion is certainly doubtful, if not untenable; but as a matter of theology it is a question of very little importance.
Whether this passage proves it or not, it is certainly true that faith is the gift of God. It exists in the mind only when the Holy Spirit produces it there, and is, in common with every other Christian excellence, to be traced to his agency on the heart. This opinion, however, does not militate at all with the doctrine that man himself “believes.” It is not God that “believes” for him, for that is impossible. It is his own mind that actually believes, or that exercises faith; see the notes at Rom_4:3. In the same manner “repentance” is to be traced to God. It is one of the fruits of the operation of the Holy Spirit on the soul. But the Holy Spirit does not “repent” for us. It is our “own mind” that repents; our own heart that feels; our own eyes that weep - and without this there can he no true repentance. No one can repent for another; and God neither can nor ought to repent; for us. He has done no wrong, and if repentance is ever exercised, therefore, it must be exercised by our own minds. So of faith. God cannot believe for us. “We” must believe, or “we” shall be damned. Still this does not conflict at all with the opinion, that if we exercise faith, the inclination to do it is to be traced to the agency of God on the heart. I would not contend, therefore, about the grammatical construction of this passage, with respect to the point of the theology contained in it; still it accords better with the obvious grammatical construction, and with the design of the passage to understand the word “that” as referring not to “faith” only, but to “salvation by grace.” So Calvin understands it, and so it is understood by Storr, Locke, Clarke, Koppe, Grotius, and others.
It is the gift of God - Salvation by grace is his gift. It is not of merit; it is wholly by favor.
Of course, I cannot state whether I agree with him on this point or not. I did find another commentary equally interesting, which is an editorial note I have in my copy of Gill's Exposition of the Bible:
I asked the following question from a Greek and Hebrew professor:
"In this verse, to what does the word "that" refer to? Adam Clarke, Wesley & company say that it is neuter plural and "Faith" is feminine hence it cannot refer to faith, (Such an admission would destroy their theological system.) However "Grace" is also feminine as is "Salvation".''
His reply was:
"Here you ask a wonderful theological/exegetical question to which I can only give an opinion, and not a definitive answer. The problem is that there is NO precise referent. Grace is feminine. Faith is feminine. And even Salvation (as a noun) is feminine. Yet it must be one of these three at least, and maybe more than one, or all three in conjunction. Since all three come from God and not from man, the latter might seem the more likely. However, it is a tautology to say salvation and grace are "nor of yourselves," and in that case it certainly looks more like the passage is really pointing out that man cannot even take credit for his own act of faith, but that faith was itself created by God and implanted in us that we might believe (i.e. the normal Calvinistic position). In which regard the whole theological issue of "regeneration preceding faith" comes into play. So, that is basically my opinion, though others obviously disagree strenuously, but from an exegetical standpoint, the other positions have to explain away the matter of the tautology.''
Whether you accept the reply or not, it is sufficient to show that the Greek is not as definitive in this verse as some scholars would have you believe.
Again, I must say that I cannot agree with or disagree with this person's view, especially since the quote here presented does not actually provide much of a view either. I find these two comments quite interesting though, and I hope that they are of some benefit to you.