It illustrates the 2nd.
“A well regulated militia being necessary.............”
Exactly right. The Massachusetts events were still fresh in the minds of the Framers when they drafted the Constitution and Bill of Rights. During the 1787–1788 ratification debates and the 1789 congressional discussions on the Bill of Rights, references to the need for a well-regulated militia (to avoid reliance on a dangerous standing army) and the right of the people to keep and bear arms echoed the lessons of 1774–1775.
The sequence—from the Powder Alarm’s mass mobilization to the “shot heard round the world”—underscored that an armed and organized populace was vital for securing a free state.
This historical experience helped embed the militia clause and arms right into the Second Amendment’s text and purpose.