The phrase "people of the land" comes from the Hebrew ‘Am-Ha’arets. In a generic sense, 'Am-Ha'arets referred to a political or ethnic group of people, like:
The Hittite sons of Heth (Genesis 23:7)
The Egyptians (Genesis 42:6)
The Israelites (Exodus 5:5)
The nations of Canaan (Numbers 13:28; Nehemiah 9:24)
The Ammonites (Numbers 21:34)
As Israel grew into a nation, the meaning changed. The term came to mean the common people who were not part of the religious or political leadership (2 Kings 11:14–20; 25:3; 2 Chronicles 33:25; Jeremiah 52:25). After many Jews returned from exile in Babylon, the term took on a new meaning. It described Jews who had married people from other nations. Ezra and his followers usually avoided these mixed-marriage families (Ezra 4:4; 10:2, 11; Nehemiah 10:28–31). Later, rabbinic Judaism called Jews who could not follow the whole law 'Am-Ha'arets.