The Grace Prayer is based on Paul's prayer at the end of 2 Corinthians 13: -
May the grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with you all.
(2 Cor 13:14, NIV Bible)
to which have been added the words "Now and evermore, Amen." It is common practise in church meetings for the whole congregation to say the grace prayer outloud, and to each other.
It is usual for Methodist Churches to close their meetings with this prayer. In John Wesley's Bible Notes, we see an insight into the importance of this blessing to the life of the church. Wesley warns that it should not be taken with disrespect:-
John Wesley's Bible Notes
(2 Corinthians 13:14)
"It is with great reason that this comprehensive and instructive blessing is pronounced at the close of our solemn assemblies; and it is a very indecent thing to see so many quitting them, or getting into postures of remove, before this short sentence can be ended. How often have we heard this awful benediction pronounced! Let us study it more and more, that we may value it proportionably; that we may either deliver or receive it with a becoming reverence, with eyes and hearts lifted up to God, "who giveth the blessing out of Sion, and life for evermore.""