“Not like these in the Portion of Yaakov, For it is He who formed all things; And Yisrael is His very own tribe. LORD of Hosts is His name.” JEREMIAH 51:19 (The Israel Bible™)
In the previous two chapters, Yirmiyahu (Jeremiah) describes the utter destruction that will befall the Babylonians. However, it is the future of Israel that concerns God the most. The Babylonians put their trust in idols are are let down in the end. Israel’s fate is different because they trust in Hashem (God). Since Hashem created the world, it is His to distribute as He pleases. He chose to give the Land of Israel to the People of Israel, the “portion of Yaakov”, as an enteral inheritance that will remain theirs forever.