The word "Israel" here represents all the people of Israel. Alternate translation: "The people of Israel are my own children" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Here the people of Israel are spoken of as if they were a firstborn son who causes joy and pride. Alternate translation: "is like my own firstborn son" (See: [[rc://en/ta/man/translate/figs-metaphor]])