Johan, I stand with you in disagreement of the quoted text, a conclusion to which I came while still reading that quote, before having reached your own second paragraph. It has long been my understanding that it is the Son whom we see in the O.T.

John tells us that no one has seen God at any time; this in reference to the Father. Yet, we have the numerous O.T. theophanies, as you mentioned.

But I appreciate also the reason you gave, that Christ (not Mary!) is the only mediator between God and man. This tells us perfectly that those theophanies must have been Christophanies, since no man speaks to the Father, nor is spoken to by the Father, except through the Son.

Meta4

There is no such thing as preaching Christ and Him crucified, unless we preach what nowadays is called Calvinism. It is a nickname to call it Calvinism; Calvinism is the gospel, and nothing else. - C.H. Spurgeon