You might be referring to this (abridged) conversation between Leto and Stiglar. (Children of Dune P. 65/73)
Sietch Tabr - The Attendant:
Stilgar cleared his throat. Leto spoke without turning: "I have a
very serious problem, Stil." "So I surmised." The voice beside Leto
came low and wary. The child had sounded disturbingly of the father.
"My problem is that my father left so many things undone," Leto said.
"Especially the focus of our lives. The Empire cannot go on this way,
Stil, without a proper focus for human life. I am speaking of life,
you understand? Life, not death."
Leto and Stilgar talk about the past, leadership responsibilities, Fremen tradition, and how the deeper tradition that lay in Leto's mind would change society in uncounted ways. Then the conversation's brought to a halt by Stilgar's abbrupt turning and walking away:
Stil, I charge you to save people. They're more important than things.
And Ghani is the most precious of all because, without me, she is the
only hope for the Atreides." "I will hear no more," Stilgar said. He
turned and began climbing down the rocks toward the oasis across the
sand. He heard Leto following. Presently Leto passed him and, glancing
back, said: "Have you noticed, Stil, how beautiful the young women are
This last simple observation by Leto sets a cascade of thoughts in Stilgar's mind.
Stilgar could not explain it, but he found Leto's casual observation
profoundly disturbing. It ground through his awareness all the way
back across the sand to Sietch Tabr, taking precedence over everything
else Leto had said out there on The Attendant. Indeed, the young
women of Arrakis were very beautiful that year. And the young men,
too. Their faces glowed serenely with water-richness. Their eyes
looked outward and far. They exposed their features often without any
pretense of stillsuit masks and the snaking lines of catchtubes.
Frequently they did not even wear stillsuits in the open, preferring
the new garments which, as they moved, offered flickering suggestions
of the lithe young bodies beneath.
Why did I want the village destroyed? Stilgar wondered, and he
stumbled as he walked. He knew himself to be of a dying breed. Old
Fremen gasped in wonder at the prodigality of their planet -- water
wasted into the air for no more than its ability to mould building
bricks. The water for a single one-family dwelling would keep an
entire sietch alive for a year. The new buildings even had
transparent windows to let in the sun's heat and to desiccate the
bodies within. Such windows opened outward.
The very meaning of sietch -- a place of sanctuary in times of trouble
-- had been perverted here into a monstrous confinement for an entire population. Leto spoke the truth: Muad'Dib had changed all that.
The old ways (My ways! he admitted) had forced his people to ignore
all history except that which turned inward onto their own travail.
With an abrupt shock, Stilgar realized that these things were equally
dangerous to the course which Alia was setting. Again Stilgar
stumbled and fell farther behind Leto.
Change is dangerous! Stilgar told himself. Sameness and stability were
the proper goals of government. But the young men and women were
beautiful. And they remembered the words of Muad'Dib as he deposed
Shaddam IV: "It's not long life to the Emperor that I seek; it's long
life to the Imperium." Isn't that what I've been saying to myself?
Stilgar wondered. He resumed walking, headed toward the sietch
entrance slightly to Leto's right. The youth moved to intercept him.
Muad'Dib had said another thing, Stilgar reminded himself: "just as
individuals are born, mature, breed, and die, so do societies and
civilizations and governments." Dangerous or not, there would be
change. The beautiful young Fremen knew this. They could look outward
and see it, prepare for it.
Stilgar was forced to stop. It was either that or walk right over
Leto. The youth peered up at him owlishly, said: "You see, Stil?
Tradition isn't the absolute guide you thought it was."