Psalms 129:8

Neither do they which go by say, The blessing of the Lord,... - As in a harvest-field, where persons passing by express their joy and gratitude that their neighbors are reaping an abundant harvest. The phrase “The blessing of the Lord be upon you,” was expressive of good wishes; of pious congratulation; of a hope of success and prosperity; as when we say, “God be with you;” or, “God bless you.” The meaning here is, that such language would never be used in reference to the grass or grain growing on the house-top, since it would never justify a wish of that kind: it would be ridiculous and absurd to apply such language to anyone who should be found gathering up that dry; and withered, and worthless grass. So the psalmist prays that it may be in regard to all who hate Zion Psalms 129:5, that they may have no such prosperity as would be represented by a growth of luxuriant and abundant grain; no such prosperity as would be denoted by the reaper and the binder of sheaves gathering in such a harvest; no such prosperity as would be indicated by the cheerful greeting and congratulation of neighors who express their gratification and their joy at the rich and abundant harvest which has crowned the labors of their friend, by the prayer that God would bless him.

We bless you in the name of the Lord - Still the language of pious joy and gratification addressed by his neighbors to him who was reaping his harvest. All this is simply language drawn from common life, uttering a prayer that the enemies of Zion might be “confounded and turned back” Psalms 129:5; a prayer that they might not be successful in their endeavors to destroy the Church. Such a prayer cannot but be regarded as proper and right.