All is as the Force wills it.

In Rogue One: A Star Wars Story, there's this line of Chirrut: All is as the Force wills it.
Its context is provided in this Guardian article, and I quote:

While searching for a lead on the whereabouts of Saw Gerrera (Forrest Whitaker) on Jedha, Jyn and Cassian encounter blind warrior-monk Chirrut Îmwe (Donnie Yen), a strong believer in the Force who has many Jedi-like abilities. His frequently repeated mantra—"I am with the Force, the Force is with me"—embodies the Jedi belief that the Force is ever-present and all-powerful. "I fear nothing," he says. "All is as the Force wills it."

My question concerns the meanings of is, as and it in that sentence.

Is is a linking verb here or does it simply mean "exist"?

Does as mean "in the way that" or "because"?
And what does it refer to?