Torah Among the Gentiles

I've been asked a few times how to understand the saying of the Sages: "If someone tells you that there is wisdom among the gentiles, believe it. If he tells you that there is Torah among the gentiles, do not believe it." If that is the case, how can I utilize modern commentaries on the Bible written by Christians?

I posted an answer to Avodah from R. Hershel Schachter's recent TorahWeb devar Torah. R. Schachter wrote:

But at the same time the religious Jew has his own unique outlook on life and style of living. The tradition of the Talmud was, based on the possuk in Eicha (2:9), that although there is much chochma (knowledge and wisdom) to be gained from the secular world, but 'Torah' (teaching a way of life and an outlook on the world) can not be picked up from the other disciplines. These can only be acquired through the revealed truths of the Torah.

He understands "Torah" to mean a way of life and not insights into Torah texts. While this is all part of a derashah rather than a pesak, I don't know that it is out of place to take this seriously considering that the source of the statement is itself a midrash.

Would R. Schachter jump at the opportunity to hear Christian scholars teaching Torah? Probably not. But he might not object to a good peshat he hears that happens to originate in a non-Jewish source (as, for example, the Abarbanel does often in his commentary to Tanakh).