What does Ezekiel 23:4 mean?

The older one was named Oholah, and her sister was Oholibah. They became mine, but both acted like prostitutes. Oholah stands for Samaria, and Oholibah for Jerusalem. Ezekiel 23:4 - Modern Text Bible

(The sisters represent Samaria (the northern kingdom) and Jerusalem (the southern kingdom), both unfaithful to God.)