Nicene and Post-Nicene Fathers, Ser. II, Vol. XI:
The Works of John Cassian.: Chapter XIV. Of Thanksgiving.

Chapter XIV.

Of Thanksgiving.

Then in the fourth place there stand thanksgivings which the mind in ineffable transports offers up to God, either when it recalls God’s past benefits or when it contemplates His present ones, or when it looks forward to those great ones in the future which God has prepared for them that love Him. And with this purpose too sometimes we are wont to pour forth richer prayers, while, as we gaze with pure eyes on those rewards of the saints which are laid up in store hereafter, our spirit is stimulated to offer up unspeakable thanks to God with boundless joy.