Can "gēns" be used to exclude outsiders, as in English "Gentile"?

Question

I'm examining a work by Tertullian, Adversus Iudaeos, and in it he uses the word "gentibus" in a way that seems to indicate peoples or nations:

Hunc enim oportebat pro omnibus gentibus fieri sacrificium (13.21)

But Thewall's translation renders it this way:

For Him it behoved to be made a sacrifice on behalf of all Gentiles

Sure enough, my Latin dictionary app gives "Gentile" as a possible translation of gēns, but Wiktionary doesn't, though it gives "heathen" or "pagan" for the derivative gentilis.

Is it typical for gēns to imply the "otherness" of peoples, as English Gentile means "non-Jew"? Or is that a rare/non-standard usage, or perhaps a later development?

Answer 1

From Lewis & Short:

c. In the eccl. fathers, gentes, like ἔθνος, opp. to Jews and Christians, pagan nations, heathen, gentiles, Lact. 2, 13 fin.; Vulg. Psa. 2, 1 et saep.— Hence the title of Arnobius's work, Adversus Gentes.—

Even in the text you're reading, passage 2 to me provides unambiguous attestation for the reading:

Nam occasio quidem defendendi etiam gentibus [sibi] divinam gratiam hinc habuit praerogativam, quod sibi vindicare dei legem instituerit homo ex gentibus nec prosapia Israelitum Iudaeus.

For the occasion, indeed, of claiming Divine grace even for the Gentiles derived a pre-eminent fitness from this fact, that the man who set up to vindicate God's Law as his own was of the Gentiles, and not a Jew of the stock of the Israelites.

The bold part has to mean that there's a difference between homo ex gentibus and Iudaeus.

Answer 2

In Christian usage gentes is a translation of ἔθνη, which already in the Septuagint translates Hebrew gōyīm as the designation of the (non-Jewish) “nations”.

Answer 3

By the time of Tertullian, gens was readily understood as 'nation' or 'people'. Rather later, there is the Venerabilis Baedae Historia Ecclesiastica Gentis Anglorum, in which by gens Bede is clearly referring to nations or peoples, in England by it particularly distinguishing between the various well-defined groups such as the Mercii and Nordanhymbri, and not necessarily any of them from the Jews.

There are relevant references scattered throughout the work itself. Book III, Ch. IV, for instance, is titled Quando gens Pictorum fidem Christi perceperit, and II, XVII has gens Nordanhymbrorum.