'First Day' in the Bible

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

For upon the first day of the first month he began to go up from Babylon, and on the first day of the fifth month he came to Jerusalem, according to the good hand of his God upon him.

And the children of the captivity did so. And Ezra the priest, with certain heads of the fathers' houses, according to their fathers' houses, and each of them by name, were set apart, and sat down in the first day of the tenth month to examine the matter.

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