You are the Son of the living God. (Matthew 16:16)
St. Peter confessed that Jesus Christ is the Son of God, and that God lives. He exists; He lives.
The Lord Jesus Himself certainly taught that God lives. God sees in secret. He cares for every sparrow and every flower of the field. He counts the hairs on our heads. He makes the sun shine and the rain fall on the just and the unjust. He knows the human heart and demands honesty. He is the God of the living, not the dead. His kingdom comes. He seeks the lost. He forgives sins. His Word is truth. He wills the salvation of man. He begets children by the Holy Spirit. God is alive.
Jesus teaches this. St. Peter confessed it. The Church believes it. God lives. God is infinitely more alive than we are. Our life comes from His life. Sure: our parents gave each of us life. But who gave it to them? Okay, well, who gave it to our grandparents? Who gave it to our great-grandparents? Etc., etc. Who gave it to Adam and Eve? And who sustains us in existence? Who gives us hope and the prospect of life without end?
God the Father of our Lord Jesus Christ, that’s Who. The Lord Jesus testified that all of the life He Himself has comes from the Father. And Jesus promised to share that undying life with everyone who believes.
With St. Peter and all his successors, we believe this. We believe that God lives, and that Jesus lives, and that all the saints live. The Church stands on this faith, and our faith is true. The gates of hell cannot prevail against the Church, because the gates of hell cannot prevail against the truth. They cannot prevail against the vigor of God.