מגן אברהם

לע"נ ר' יואל בן ר' פנחס הלוי

In davening we say מגן אברהם - Hashem is the "shield" of Avraham.

Why does Avraham need a shield and why does that get a special bracha??

Unkelos [Shmos 21] translates the word חנם as מגן. Meaning that the translation can also be "free". OK, great. So why do we say "the free of Avraham". Jews like bargains and "What's better than a good meal? A free meal", but why a special bracha?

Explains the Maharal [Gvoros Hashem end of Ch. 6] - Chesed is a mitzva for which we eat the fruits in this world but the principal is saved for the next world [אוכל פירותיהם בעולם הזה והקרן קיימת לעולם הבא]. So when we receive reward for chesed, the middah of Avraham, it is for "free", because we lose nothing in the next world.

ברוך אתה השם מגן אברהם