The following is the text of the Mayflower Compact. It's written in King James' English. While leaving the original language, I have taken the liberty of updating spelling to make it easier for you to read.
In the name of God, Amen. We whose names are underwritten are subjects of our sovereign Lord King James and by the grace of God, of Great Britain, of France, and Ireland king and defender of the faith.In other words, the original Mayflower Compact was a covenant dedicating the nation to God, and setting up a civil government under His name.
Having undertaken for the glory of God, and the advancement of the Christian faith and honor of king and country, a voyage to plant the first colony in the northern part of Virginia do by these presents solemnly and mutually in the presence of God, and of one another, covenant and combine ourselves together into a civil body politic; for our better ordering, and preservation and furtherance of the ends aforesaid; and by virtue hereof, to enact, constitute, and frame such just and equal laws, ordinances, acts and Constitutions, from time to time, as shall be thought most meet and convenient for the general good of the colony: unto which we promise all due submission and obedience. In witness whereof we have hereunder subscribed our names at Cape Cod the 11 of November, in the year of our sovereign Lord King James of England, France, and Ireland the eighteenth and Scotland the fify-fourth. Anno-Domani 1620.
David Barton has more on the history of Thanksgiving: