Vague as that citation offered by that page was (which was fairly obviously copied), I managed to use it to figure it out, so thanks for providing it. It turns out it's from the
Second Epistle of Clement. The name "Second Epistle of Clement" is actually inaccurate given that it wasn't by Clement (though for a while it was attributed to him, hence the name) and it isn't an epistle, but rather an anonymous sermon. This is presumably why the Liturgy of the Hours used the more accurate statement of "a homily written in the second century". Unfortunately, it also made it
way harder than it should have been to figure out where it was from; I wish it had said it was from "a homily written in the second century
attributed to Clement" which keeps things reasonably accurate and makes it easier to figure out where it's from.
Anyway, it's Chapters 13 and 14 of the work (the quote in the opening post from the Liturgy of the Hours omits a little of the start of Chapter 13). The Second Epistle of Clement can be read in its entirety here, albeit in a different translation:
In case anyone is wondering the convoluted process that led to me figuring this all out (and it was
very convoluted), I'll include it here.
The mention of the Office of Readings was the first step. Thankfully someone has it all available online. The Thursday of the 32nd Week of Ordinary time (for this year, anyway) can be found
here. Scroll down to "second reading" and you'll see it. It says it's "from a homily written in the second century."
Unfortunately, it gives no further information about who wrote this homily, nor what "(Cap. 13, 2-14, 5: Funk 1, 159-161)" is. Sometimes weird citations like that are just taken from older books, so I searched for the phrase in Google Books and something that popped up was a printed version of Liturgy of the Hours. It was in snippet view so I couldn't see much other than that it was in it and apparently listed as the source of a reading, but the good news is that the work in question was available--in full--on The Internet Archive, although it requires you to get a free account to read it. You can find it
here.
Looking at some other readings listed, it appears the first part of the citation refers to the chapter/verse of the work being cited. For example, on
page 56 we see a reading that it says is from the Epistle of Barnabas ("Epistle attributed to Barnabas" is what it says), which it cites as: "Cap. 1. 1-8; 2, 1-5: Funk 1, 3-7)." And if we look at
chapter 1 and
chapter 2 of the Epistle of Barnabas, we can see that the context lines up perfectly (although the linked translation omits verse numbers). Granted, the citations can be a little weird here.
Page 326 offers a portion from Polycarp's letter to the Philippians, and cites it as "Cap. 9, 1-11, 4: Funk 1, 275-279". And we can see its content in chapters 9-11 of the letter (available
here).
Unfortunately, that ultimately left me no closer to figuring out where this homily is from or can be found (knowing where in the homily the excerpt is from is not useful if I don't know where the homily is!), or any information on what the "Funk" is supposed to mean. So in a bit of random desperation, I just thought to search the Catholic Encyclopedia for "Funk" (that is, search "site:newadvent.org/cathen funk") to see if maybe it was someone important, and I find there was a guy named
Franz Xaver von Funk. I looked into a list of his works (his
Wikipedia page lists them more conveniently than the Catholic Encyclopedia does) and figured that what was probably in mind was "Opera Patrum apostolicorum, 2 vols., 1878–1881; 2nd ed., 1901." (as it specifies it has two volumes and the title indicates it would contain early works).
Here we find page 159 in the original edition. Remember that the citation given was "(Cap. 13, 2-14, 5: Funk 1, 159-161)". And what do you know, page 159 contains chapter 13, or XIII as they write in the Latin. The quotation says "Cap. 13, 2-14", so we see what we get in the second verse of Chapter 13, which reads in the Latin:
"Dicit enim etiam Dominus: Omnino nomen meum blasphematur in omnibus gentibus, et iterum: Vae illi, propter quem blasphematur nomen meum."
I'm citing the Latin rather than the Greek (the work includes the Greek original and a Latin translation) because it's way easier to type up and I know Latin better than Greek. I know enough Latin to recognize this as the quote (and even if I didn't, it can be confirmed by popping this into an automated translator--Latin to English machine translation is far from perfect, but is leagues ahead of it where it was a few years ago). And this ends up answering the "Cap. 13, 2-14, 5". It's saying it's 13:2
to 14:5 (I was very puzzled for a while, thinking it was saying there were fourteen verses in chapter 13, even though there are only four). Anyway, with the fact it says "II Clementis Ad. Cor." at the top of the page, I recognize it as the Second Epistle of Clement.
And thus the mystery is solved! I told you it was a convoluted process. Most of the above was actually being typed up by me while I was trying to figure it out, as I didn't think I'd end up finding the answer and just wanted to share the information I did find for other people's benefit, but then I ended up solving it.