“Behold, the former things have come to pass, Now I declare new things; Before they spring forth I proclaim them to you.” (Isaiah 42:9)

“Behold, the former things have come to pass; hitherto the Lord has helped his church, has supported her under former burdens, relieved her in former staits; and this in performance of the promises made to the fathers. 

And now new things do I declare. Now I will make new promises, which shall as certainly be fulfilled in their season as old ones were; now I will bestow new favors, such as have not been conferred formerly. Old Testament blessings you have had abundantly; now I declare New Testament blessings, not a fruitful country and dominion over your neighbours, but spiritual blessings in heavenly things. 

Before they spring forth in the preaching of the gospel I tell you of them, under the type and figure of the former things.” Note, The receipt of former mercies may encourage us to hope for further mercies; for God is constant in his care for his people, and his compassions are still new.

“Matthew Henry’s Commentary on the Whole Bible”