“The explanation for "free software" is simple — a person who has grasped the idea of "free speech, not free beer" will not get it wrong again.”

2010s, Who's too Weak to Live with Freedom? (2013)

1990s, Why "Free Software" is better than "Open Source" (1998)
Context: While free software by any other name would give you the same freedom, it makes a big difference which name we use: different words convey different ideas.
In 1998, some of the people in the free software community began using the term "open source software" instead of "free software" to describe what they do. The term "open source" quickly became associated with a different approach, a different philosophy, different values, and even a different criterion for which licenses are acceptable. The Free Software movement and the Open Source movement are today separate movements with different views and goals, although we can and do work together on some practical projects.
The fundamental difference between the two movements is in their values, their ways of looking at the world. For the Open Source movement, the issue of whether software should be open source is a practical question, not an ethical one. As one person put it, "Open source is a development methodology; free software is a social movement." For the Open Source movement, non-free software is a suboptimal solution. For the Free Software movement, non-free software is a social problem and free software is the solution.

On the kde-licensing mailing list, (13 April 1998) https://marc.info/?l=kde-licensing&m=89249041326259&w=2
1990s

2000s, What is free software? (2006)

Why Schools Should Exclusively Use Free Software (2003) http://www.gnu.org/education/edu-schools.html
2000s
Context: Free software permits students to learn how software works. Some students, on reaching their teens, want to learn everything there is to know about their computer and its software. They are intensely curious to read the source code of the programs that they use every day. To learn to write good code, students need to read lots of code and write lots of code. They need to read and understand real programs that people really use. Only free software permits this.
Proprietary software rejects their thirst for knowledge: it says, “The knowledge you want is a secret — learning is forbidden!” Free software encourages everyone to learn. The free software community rejects the “priesthood of technology”, which keeps the general public in ignorance of how technology works; we encourage students of any age and situation to read the source code and learn as much as they want to know. Schools that use free software will enable gifted programming students to advance.

"Quotes", The Educated Imagination (1963), Talk 6: The Vocation of Eloquence

Address at Columbia University (1991)
Context: "Our lives teach us who we are." I have learned the hard way that when you permit anyone else's description of reality to supplant your own — and such descriptions have been raining down on me, from security advisers, governments, journalists, Archbishops, friends, enemies, mullahs — then you might as well be dead. Obviously, a rigid, blinkered, absolutist world view is the easiest to keep hold of, whereas the fluid, uncertain, metamorphic picture I've always carried about is rather more vulnerable. Yet I must cling with all my might to … my own soul; must hold on to its mischievous, iconoclastic, out-of-step clown-instincts, no matter how great the storm. And if that plunges me into contradiction and paradox, so be it; I've lived in that messy ocean all my life. I've fished in it for my art. This turbulent sea was the sea outside my bedroom window in Bombay. It is the sea by which I was born, and which I carry within me wherever I go.
"Free speech is a non-starter," says one of my Islamic extremist opponents. No, sir, it is not. Free speech is the whole thing, the whole ball game. Free speech is life itself.

A Plea For Free Speech in Boston (10 December 1860), as contained in Words That Changed America https://en.wikiquote.org/wiki/Special:BookSources/1461748917, Alex Barnett, Rowman & Littlefield (reprint, 2006), p. 156
1860s

Counterterrorism and Cybersecurity: Total Information Awareness (2nd Edition), 2015