For whatever promises are of God are, in him, Yes. For this reason, too, through him: Amen to God for our glory
Other versions
King James Version
For all the promises of God in him are yea, and in him Amen, unto the glory of God by us.English Standard Version
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.New International Version
For no matter how many promises God has made, they are "Yes" in Christ. And so through him the "Amen" is spoken by us to the glory of God.