Matthew 20:12

(12) But one hour.—Literally, in what was probably the technical language of labourers, made but one hour:

The burden and heat of the day.—The word rendered “heat” is elsewhere used—as in James 1:11, and the LXX. of Jonah 4:8—for the “burning wind” that often follows on the sunrise, and makes the labour of the first half of the day harder than that of the latter.