For much in the early paragraphs of this chapter we are indebted to an able discussion of the character of the Sinaitic covenant by Robert Balfour, which appeared in the British and Foreign Evangelical Review of July 1877.
After much searching, I was able to find this particular journal article, linked below, at archive.org. The article begins on journal page 511, which is roughly page 521 of the scan. Give it a read to find out what brother Pink found so remarkable.
Balfour, Rev. R. G. (1877). The Sinai Covenant. The British and Foreign Evangelical Review, XXVI, 511-526.