1 Corinthians 1:3 (ESV)

3 Grace to you and peace from God our Father and the Lord Jesus Christ.

When it comes to the greeting, Paul again adapts standard formulas to suit his theological purposes. From the familiar Greek greeting chairein (literally, rejoice), he derives the word charis, which means grace. This word is filled with theological significance, pointing to God’s undeserved love which he has bestowed on believers in Jesus Christ.

To the word grace Paul also adds the word peace, thereby drawing on the standard Hebrew greeting shalom (literally, peace or well-being). 

Paul’s greeting is actually a prayer to God the Father and Jesus Christ to bless the church with grace and peace. Whether this form of greeting was also used in church gatherings in Paul’s time, is unknown to us. In any case, it soon became a customary greeting in the gatherings of the early church.