The Australian Constitution is a document that contains the laws governing Australia. All Australian governments must obey these laws. From 1898 to 1900 the constitution was voted on by citizens of the colonies in referendums. This means that the people who voted in the referendums had to agree that the constitution was just the way they wanted it.
A preamble is an introduction to a document. It tells people who read it some very important things about what is in the document. The preamble to the Australian Constitution begins:
"Whereas the people of New South Wales, Victoria, South Australia, Queensland and Tasmania humbly relying on the blessing of Almighty God have agreed to unite in one indissoluble Federal Commonwealth under the Crown of the United Kingdom of Great Britain and Ireland, and under the Constitution hereby established..."
Many people signed petitions to have the words "Almighty God" included. This was saying they wanted the Constitution of Australia to state that God is the true ruler of Australia.