Note 2 at 2 Th. 1:2: Grace and peace came to be normal greetings of the Christian community. Grace is God's ability towards us on an undeserved, unmerited basis (see ref. k at this verse). Peace is the result of God's grace within the heart of those who receive it. So, Paul is evoking God's grace towards us and our acceptance of it which results in peace (see ref. l at this verse).