'First Day' in the Bible

From the first day of the seventh month they began to offer up burnt-offerings to Jehovah. But the foundation of the temple of Jehovah was not yet laid.

And the children of the captivity did so. And Ezra the priest and certain of the chief fathers were separated according to their fathers' houses, and all of them expressed by name; and they sat down on the first day of the tenth month to examine the matter.

And they ended with all the men that had taken foreign wives by the first day of the first month.