Let's be honest, everyone who read the comic wanted this.
"Put it on."
Batman looked at the ring Hal Jordan held out to him.
"Why?"
"This ring helped me overcome my greatest fear, it can help you overcome yours… the night of your parent's death."
There was a long moment of silence.
Finally, Batman said,
"That moment made me who I am. I can't forget it. I won't forget it."
"I'm not asking you to forget it. Just think back to that moment all those years ago, when the Batman was born. Think back to it, accept it, and live with it, control it."
Hal sighed. "Bruce, you don't have to live with that fear anymore. You have done more than any of us to make the world a better place. Let it go." He lowered his voice. "It's what your parents would have wanted."
Batman didn't respond. His face was inscrutable behind the mask. Hal was never quite sure, but he though that he detected a wisp of a tear in the eye of the Dark Knight.
At last, the dark hand reached out, and took the ring.
"Hal, I have lived my life in darkness. To honor my parents, I became one with the night. I am the night. But nothing stays hidden forever, perhaps it's time…"
He slipped the ring onto his finger.
"...to step into the light."
A explosion of green energy erupted from Bruce, knocking Hal off his feet and sending shock waves through the Earth. Hundreds of bats created by green energy materialized into the air, flitting to and fro, eyes shining like the purest of emeralds. Hal stood up, trying to catch a glimpse of Bruce, who was hidden from sight by a swirling vortex of green bats. Finally, the curtain of bats parted for a moment. And there stood the Batman, but not the Batman that Hal Jordan had once known.
Bright viridescent light shone from his armor, almost blinding Hal. From the Green Lantern symbol emblazoned on his chest spread two bat wings. His cape billowed around him like a emerald cloak, and his verdant eyes burned with an intensity Hal had never seen before in any living being.
Batman slowly held up his hand in acknowledgment, the ring shining on his fist. No words were spoken. None were needed. And Hal Jordan suddenly knew, that darkness could hide from the light no longer.
If anyone wants to expand on this, feel free.