Is it considered plagiarism if you use bible verses from the bible while writing a children’s christian storybook?
If so, how would I go about getting permission?
It really depends on the book being used and when it was copyrighted. Bible publishers almost always give the scriptures their own interpretation (their own wording) and they’re copyrighted.
Briefly quoting is fine. Be sure to credit that particular bible in your book, of course.
There are ways to quote scripture. This page tells you how: https://www.mtso.edu/library/citing_the_bible.htm
You can read about copyright law here: https://www.copyright.gov/laws/