Each state must accept and agree to follow the decisions of the United States in Congress assembled. The states must follow all of the rules as stated in the Articles of Confederation. The union of states is meant to last forever. No alterations can be made to the Articles without the agreement of Congress and the confirmation by each of the state legislatures.
Each of the delegates that sign this document has the power to commit the state that they represent to all of the Articles and their specific contents. The people of each state will agree to follow the rulings of Congress on all matters they discuss, and each of the states agrees to never violate the union. We have signed this as members of Congress, meeting in Philadelphia, Pennsylvania on July 9, 1778, the third year of American Independence.
Article 13 and the conclusion provide the means by which the Articles will be enforced and establishes the process for amendment to the Articles of Confederation.
The authority of the government established by the Articles rests in the pledge of all of the delegates to respect the union of thirteen states forever. This forces each individual state to rely on the honor of each of the other states to fulfill their mutual commitments. This reflects a notion similar to the "friendship" promise of Article 2, which had already been demonstrated to be ineffective.
The farther removed the states felt from the threat of war, the less they cared about honoring their pledge to abide by the Articles. In the absence of a strong and coercive power to force states into compliance, states failed to send delegates to Congress, were delinquent on contributions to the general treasury, negligent regarding the matters of foreign commerce, and eager to take power into their own hands. When the need for mutual defense was removed, there seemed to be little need for a central government whose authorization solely covered things related to the common defense.
The significance of this portion of the Articles of Confederation lies not only in demonstrating the weakness of the government from 1781-1789, but also because it provided the means through which the Articles could be revised and the U.S. Constitution could be formed.
Although this Article states that the union cannot be violated by any state, it does allow for amendment to the Articles through agreement in Congress and approval by each of the state legislatures. The convention of all states, except for Rhode Island, in Philadelphia in May 1787, met under this guise to "amend" the Articles, not replace them. When the new and radically different document was adopted by this convention, it had to be ratified by all of the states before it took effect.
It is questionable whether this transition between the Articles of Confederation and the Constitution was legal at all. The Articles stated that Congress had to agree to amendments, and the convention was not Congress. However, given the weakness of the Congress and the strength of the states, it would have been futile to try to stop it. Plus, Congress, more than any other group, probably understood the difficulties inherent in a powerless central government, and therefore welcomed the chance for increased powers after being so long held captive by the supreme sovereignty of the states.
The transition from Articles to constitution was somewhat in the spirit of Thomas Jefferson's Declaration of Independence, which stated that a people have a right to overthrow a government that does not protect its fundamental rights. This time, however, the people did not demand a more democratic government that put sovereignty solely in the state, but clamored for a stronger central government that had a better chance of protecting their property from the chaos of too many competing state governments.