1. Exposition

How would the labourers have been paid?

Ezra 3:7 (ESV)

7 So they gave money to the masons and the carpenters, and food, drink, and oil to the Sidonians and the Tyrians to bring cedar trees from Lebanon to the sea, to Joppa, according to the grant that they had from Cyrus king of Persia.

These labourers were probably paid with money taken from the treasury mentioned in Ezra 2:69. Since the areas around Babylon did not have many forests or stone quarries, the Jews probably had to hire foreigners to come and help them.