I cannot recommend 'God of Promise' enough; it's a fantastic read.

Horton's view on the Mosaic covenant is actually the same as 'classic' covenant theology.

Very briefly put, under the Mosaic Covenant salvation was by grace as it is in all ages, however the national promises such as land etc were only to be fulfilled if Israel kept faithful to the law. So Horton does see the Mosaic covenant as a reinstatement of the CofW with respect to land but not with respect to salvation. When Israel sinned and broke God’s law we see her being carried away into captivity but even in captivity we see a faithful remnant, saved not by keeping the law but by grace.

I’ve written this in a bit of a hurry but I hope that helps.

__________________
Stephen Spence

Member, Newtownards Reformed Presbyterian Church, N. Ireland