Radak (here and Tehilim 105:6): Here it clarifies that Zera Avraham is only Yisrael, and not his other seed. Hashem told Avraham "Ki v'Yitzchak Yikra Lecha Zara" (Bereishis 21:12), and Yitzchak told Yakov "va'Yiten Lecha Es Birkas Avraham Lecha ul'Zar'echa Itach" (ibid., 28:4). The Zera special to Avraham is Zera Yisrael, like the end of the verse "Bnei Yakov Bechirav."

Malbim (8): The promise [of the land] was initially to Avraham. Here it says "Zera Yisrael", for His wonders with the Aron were due to Yisrael, the father of the nation. (NOTE: In Tehilim 105:6, Malbim said that "Zera Avraham Avdo" hints to what Hashem did for Avraham because he was "Avdo", and served Him faithfully. It seems that he explains correspondingly here regarding Yakov. - PF)

Radak (Tehilim 105:6): This clarifies that "Zera Avraham Avdo" applies only to Yisrael.

Malbim (Tehilim 105:6): This shows that He chose them to be His portion ? "Yisrael Avdi Yakov Asher Becharticha" (Yeshayah 41:8). Vilna Gaon - He chose them when they were still Bnei Yakov ¹ .