"Many years later, Obi-Wan and Darth Vader duel a second time. The Sith Lord is now more experienced and powerful." -Beware the Sith
"This is a fight you cannot win, Darth. Your power has matured since I taught you" -A New Hope
"He kept his eyes inward, seeking reflection in his own bottomless core. His power was great, now, greater than it had ever been." -Return of the Jedi
"He stared at his reflection a long time. His injuries had deformed his body, left it a ruin, but they’d perfected his spirit, strengthening his connection to the Force. Suffering had birthed insight." -Lords of the Sith
Want me to find more?