Yes

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

So I am reading Future Grace by Piper and he brought up this passage and it made me stop and re-read a few times. Then I pulled out my Bible to read the section. Then I read his section on it again. All the promises God made and we see in the Bible, they have their Yes in Christ. So the way we can be sure of all that God promises is Christ. The way we know that God truly is working all things for the good of those who love Him and are called is because of Christ. The reason we are assured that Christ will lose none from those who the Father has given Him is Christ. The reason for all our hope and our life is Christ. He is the eternal Yes to all the promises in scripture. And this is why we can say Amen. Amen means "so be it" or "verily" and so it is because of Christ and the assurance of the promises of God that we can say "So be it" to whatever God wills. It is how we can say "Verily" which means 'in truth/truly' about God.
I don't know, maybe this is something simple I ought to have realized a long time ago. But today I read this and was quite amazed. God is sweet.