Commentary for Genesis 22:17

ברך אברכך I WILL SURELY BLESS THEE — The double use of the term “bless” is intended to signify a blessing for the father and a blessing for the son (Genesis Rabbah 56:11).

Like the stars of the sky and like the sand, etc.: We have found that sometimes He compares Israel to the stars and sometimes to the sand on the shore of the sea, and sometimes to dust - as it is stated (Genesis 28:14), "And your descendants shall be as the dust of the earth." It is because it all indicates different times. As in times of tranquility and success, He compares them to the stars. That is an expression of greatness, as Rashi (Rashi on Deuteronomy 1:9) explains on the verse, "The Lord, your God, has multiplied you, and behold you are today as numerous as the stars in the sky" (Deuteronomy 1:10) - "He multiplied and aggrandized you." Likewise is, "I will surely multiply you," here an expression of greatness.

וירש זרעך את שער אויביו, the meaning of the words שער אויביו is ארץ אויביו, the land of its enemies. A land surrounded by oceans and mountains is difficult to conquer. Eretz Yisrael is such a country. When one has breached the coastal defences, or conquered the mountain ranges, it is as if one had broken through the gates of the fortified walls around a city. This is why the Torah here describes such a victory as “inheriting the gates of one’s enemies.” We find a similar expression used in Nachum 3,13 פתח נפתחו שערי ארצך, “the gates of your country will be completely open.” The prophet refers to the country lying at the mercy of an invader. G’d added further: