Luke: I saw darkness. I sensed it building in him. I'd seen it in moments during his training.

-- The Last Jedi

Luke could hear more now—far more. He heard the static of pebbles and sand being washed back and forth beneath the waves. He listened to the bump of the worms pushing blindly through the dirt, building their tunnels and revitalizing the soil. He heard the muttering of the season’s last porglets as they turned inside their eggs, beneath the heartbeats of their mothers. He heard the world flooding back into his senses.

-- The Last Jedi: Expanded Edition

More confident now, Luke stretched out with his feelings, his awareness slipping lightly through the island’s tumult of life. He found Rey instantly—she was like a beacon in the Force, burning so brightly that everything around her seemed attuned to her. And Luke sensed another familiar presence. This one was far away—achingly far. But nothing so meaningless as distance could ever dim that presence in his awareness. Luke opened his eyes. “Leia,” he said.

-- The Last Jedi: Expanded Edition

Rey: But I didn't see you. Nothing from you. You closed yourself off from the Force.

-- The Last Jedi

“I saw everything,” she said. “The island, and past it I felt the stars singing. I thought my heart would explode. But I didn’t see you. Nothing from you. No light, no dark. You’ve closed yourself off from the Force.”

-- The Last Jedi: Expanded Edition

Luke reached out, the motion a blur, and a length of lightning rod flew off the roof of one of the huts.

-- The Last Jedi: Expanded Edition

Luke Skywalker walked into the hut—to find Rey and Kylo with their hands clasped, staring into each other’s eyes. “Stop!” he yelled, and flung out his hand. A burst of power hurled every stone of the hut outward from its center, scattering them around the bench where Rey and Kylo sat in astonishment.

-- The Last Jedi: Expanded Edition

On the ledge overlooking the sea, Luke Skywalker floated a few centimeters above the stone. Pebbles hovered around him. His eyes were closed and his legs crossed. His face was strained, and beneath his gray beard the tendons of his neck stood out. Tears streamed down his face as he poured his strength, his very essence, into the Force. Behind him the peak shuddered, shedding dust and chunks of debris.

-- The Last Jedi: Expanded Edition

Luke: I saw darkness. I sensed it building in him. I'd seen it in moments during his training. But then I looked inside, and it was beyond what I ever imagined. Snoke had already turned his heart. He would bring destruction and pain and death, and the end of everything I love because of what he will become, and for the briefest moment of pure instinct, I thought I could stop it. It passed like a fleeting shadow, and I was left with shame and with consequence. And the last thing I saw were the eyes of a frightened boy whose Master had failed him.

-- The Last Jedi

Worry shadows Luke’s face as he extends his hand, reaching out with the Force—reaching into the sleeping Ben’s mind.

The boy remains still, his face untroubled. And Luke’s eyes remain shut. But he can see: fire, and ruin, and the sightless eyes of the dead. And he can hear: screams, and the howl of lightsabers, and the roar of explosions.

Darkness—expanding from this slim, dark-haired boy to shroud everything—and the cacophony of terror that will accompany it. Luke draws his hand back, as if burned.The Force around Ben has always been shot through with veins of darkness, but what he’s seen is beyond anything he’d feared to find.

-- The Last Jedi: Expanded Edition

Luke got to his feet and Rey saw immediately that nothing had changed—he was still going to walk away from her, retreating to brood in silence. Furious, she swung her staff at him again—but Luke reached out, the motion a blur, and a length of lightning rod flew off the roof of one of the huts. Before Rey could blink he had intercepted the strike of her staff, the impact sending a jolt up her forearms, and knocked her backward.

Rey sprang back at him, her staff and his improvised weapon spinning and colliding as the rain poured down. She pressed the attack. The staff had never felt more comfortable in her hands, so much like a part of her. Her confidence grew and she smiled wolfishly as she saw the surprise on his face. But it was a fleeting thing. Quicker than she could follow, he parried her thrust and continued the motion, flipping the staff out of her hands to clatter on the stones, leaving her defenseless.

-- The Last Jedi: Expanded Edition