In Parshas Lech Lecha, G-d appears to Avraham after the battle with the kings, and says to him, "Anochi Magen Lach", "I am your shield." We incorporate this three times into our daily prayers (four times on Shabbat) in Shmone Esre, in the very first of the eighteen brachot, remembering our three forefathers (avot) Avraham, Yitzchak and Yaakov. But the concluding blessing only uses one of them, Magen Avraham, Shield of Avraham. Why only Magen Avraham? This particular blessing is so important that failing to concentrate on it requires repeating the Shmone Esre. What of the other Avot? What is so special about Avraham and about G-d's role as Magen Avraham, Shield of Avraham? Let us look at the three descriptions leading up to it of G-d as, Melech Ozer, Moshia UMagen, the King who Aids, Saves and Shields. Each of these praises rises in stature, as is appropriate when praising G-d, by going from the lesser to the greater. G-d as the one who aids us is the lea...