Who said "Death is not the end—it's a doorway."?

This quote is attributed to Captain Kirk.

Death is not the end—it's a doorway. - Captain Kirk

"Death is not the end—it's a doorway."

Captain Kirk Death

"To boldly go where no one has gone before."

"I've always believed that the spoon is in the mind."

"It is the nature of sacrifice that it is often done for those we love."

"You have to believe in yourself when no one else does."

"Death doesn't scare me anymore."

"Death and I are old friends."

"Welcome to my world."

"Death is just the beginning."