Charles Ellicott Commentary Matthew 20:2

"And when he had agreed with the laborers for a shilling a day, he sent them into his vineyard." — Matthew 20:2 (ASV)

A penny a day — Measured by its weight, the "penny"—i.e., the Roman denarius, which was then the common standard of value in Palestine—was equivalent to about sevenpence-halfpenny in our coinage. Its real value, however, is found in its purchasing power. As the average wage for an unskilled agricultural laborer, it may be fairly considered equal to about half-a-crown in our present currency. In other words, it was an adequate and just payment in itself.