And in Hebrews at least, the writer will cite something as applying to Christ which the OT says of God. You can see this repeatedly in Hebrews 1.
I found this interesting comment on Calvin’s understanding of this issue in Five Views on Law and Gospel in Willem vanGemeren’s chapter, pages 51-52, in which he is citing John Hesselink:
What is said of God in the Old Testament can without any twisting, manipulating or allegorising be applied to Christ in the New Testament, because when God is referred to in the bible, Christ is presupposed.
I’m looking forward to Commentary on the New Testament Use of the Old Testament, edited by Greg Beale and Don Carson, said to be available in the US in November.