Why are “Judah” and “Israel” distinguished in many verses?
Judah was one of the 12 tribes of Israel. And the word “Israel” can refer to the 12 tribes or to Jacob. The angel of the Lord changed his name from Jacob to Israel (Genesis 32:22-32). The tribe of Judah inherited land in the south of the promised land.
King Solomon was the last king to reign over a unified Israel. Beginning with his son, the kingdom was split or divided into the northern and southern kingdom. The Bible refers to the northern kingdom as “Israel.” The southern kingdom they called “Judah.”
The northern kingdom of Israel was the first to fall to the Assyrians because of the wicked Kings and the wickedness of the nation. It was more wicked than the southern kingdom, Judah. Judah still had the Temple and Jerusalem and its kings weren’t stellar but were more righteous for a longer period of time in history.
Judah fell to the Babylonians because of its wickedness. The northern kingdom of Israel fell around 720 BC while the southern kingdom of Judah lasted until 586 BC. And after 70 years the Israelites returned from the exile, rebuild the temple in Jerusalem and the city walls.
