'First Day' in the Bible

From the first day of the seventh month, they began to offer burnt offerings to the LORD; but the foundation of the LORD's temple was not yet laid.

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

The children of the captivity did so. Ezra the priest, with certain heads of ancestral houses, after their fathers' houses, and all of them by their names, were set apart; and they sat down in the first day of the tenth month to examine the matter.

They made an end with all the men who had married foreign women by the first day of the first month.