Note 6 at 2Co 1:2: This is a common Greek and Hebrew greeting that is strengthened and brought into a deeper meaning by the addition of the phrase "from God our Father, and from the Lord Jesus Christ."

By comparing this greeting with that of Peter in 2Pe 1:2, we see that grace and peace don't come just because someone speaks them over you. They come through the knowledge of God. Wrong thinking will produce turmoil regardless of who blesses you with peace.