en_tn/jer/51/19.md

the portion of Jacob

Here "Jacob" represents the people of Israel. God being their "portion" is an idiom that means that they worship him. Alternate translation: "the portion of Israel" or "whom the people of Israel worship" (See: rc://en/ta/man/translate/figs-metonymy and rc://en/ta/man/translate/figs-idiom)

the molder of all things

"the creator of all things" or "the one who created all things"

Israel is the tribe of his inheritance

This speaks of Israel belonging to Yahweh as if it were something that Yahweh gained through inheritance. Alternate translation: "The tribe of Israel belongs to him" (See: rc://en/ta/man/translate/figs-metaphor)