Genesis 12:2-3 is the Abrahamic Covenant:
“I will make you into a great nation, and I will bless you; I will make your name great, and you will be a blessing. 3 I will bless those who bless you, and whoever curses you I will curse; and all peoples on earth will be blessed through you.”
Verse 2 is God’s Domestic Policy toward Abraham and his descendants, the Jews. Verse 3 is God’s Foreign Policy toward those people and nations who interact with the Jews.
Those who blessed the Jews have been blessed in return. But, through the ages many have tried to destroy the Jews. The Bible and history show how those attempts not only failed but returned back on those as a curse.