"And now, He says, Peace I give unto you, not simply, but My peace. And this was clearly nothing else but saying: I will bring the Spirit, and of Myself will abide with those who receive Him. For that the peace of Christ is His Spirit, it needs no long argument to completely demonstrate. But I suppose one ought to say this, if He is peace in heaven and on the earth, how can it fail to be clear to everyone, that as we have said, the peace is certainly His Spirit? And indeed the inspired Paul said to some: and the peace of God, which surpasses all understanding, will guard your hearts and minds through Christ Jesus (Phil 4:7)"
St Cyril of Alexandria