I have asked this question to R Moishe Bane, the president of the OU, and he responded

> Thanks for the interest. I came across Rav Kook’s thought in an essay
> of his that I read in a rabbi’s home library in 1979. I have spent
> hours searching for the journal and have yet to track it down. I
> recall it was published in the second half of the 1920’s.

In a followup email where I told him I'd run it past two other scholars of R Kook he added

> I will owe you a big debt of gratitude if you locate the cite. I, too,
> have run it by several Rav Kook scholars who did not know the article,
> but found the message consistent with Rav Kook’s views and
> presentation.