Or HaChaim on Deuteronomy 33:29/אור החיים על דברים ל״ג:כ״ט

1 אשריך ישראל…עם נושע בשם, "Fortunate are you, O Israel; …a nation delivered by the Lord." Whereas any wars the other nations are engaged in are fought by their protective angels, and each nation is afraid that the protective angel of its adversary may prevail unless G'd smites that angel, this does does not apply in the case of Israel whose "protective angel" is G'd Himself. -Compare Exodus 14,30 where the Torah describes the Israelites seeing the protective angel of Egypt dead, as explained by Shemot Rabbah 21,5. Israel is fortunate not to have to depend on intermediaries. This enables the Jewish people to be free from fear.

2Another meaning of the words נושע בשם is that it may refer to the king of the Israelites enjoying G'd's deliverance when in difficulties. When discussing Deut. 30,3 we pointed out that since the Torah does not speak about G'd "bringing back" the exiles but about G'd "returning" (Megillah 29), this means that the Jews are in the enviable position of G'd descending into exile with them as it were, so that He returns with them to the Holy Land when the time is ripe. ואשר הוא חרב גאותיך. These words may mean: "and Who is the sword drawn against those who feel superior to you." Nobody enjoys a mightier sword than that of G'd who fights on Israel's behalf.