When Paul says,"...it is through him that we utter our Amen to God..." in 2 Corinthians, he is talking about our coming to God with faith in his promises and our praying through Christ with Jesus as our great high priest so that in Christ all the promises of God for us are "Yes and amen." Paul also says that God has"given us his Spirit in our hearts." When we pray, we can see all three persons of the Trinity at work.