He is the final answer to the OT. Jesus gathers up all the various threads of promise and hope and rescue and longing that cover the landscape of the Old Testament and snowball down through the centuries. The virtue of every OT saint is filled out in him, and the failure of every OT saint heightens the longing for him. (2 Cor. 1.20)

Dane Ortlund

20 For all the promises of God find their Yes in him. That is why it is through him that we utter our Amen to God for his glory. (2 Corinthians 1:20)