What is the meaning of the prayer from the movie 'The Boondock Saints'?

Answer 1

And Shepherds we shall be

For Thee my Lord, for Thee.

Power hath descended forth from Thy hand,

Our feet may swiftly carry out Thy commands,

So we shall flow a river forth to Thee,

And teeming with souls shall it ever be.

In Nomine Patri, Et Fili, Et Spiritus Sancti.

Answer 2

The family portion of the prayer:

"And shepards we shall be, for Thee, my Lord, for Thee. Power hath descended forth from Thy hand, that our feet may swiftly carry out Thy command. So we shall flow a river forth to Thee and teeming with souls shall it ever be."

Was in their family, and basically is what it sounds like. They give thanks to God for the power given to them, so that they can swiftly carry out his command. Then they promise to keep a river of souls ever flowing to God, being those that they kill.The family prayer, is a prayer to illustrate an oath/oration to G-d, that they will do all in their power to shepherd the weak through the evils brought forth by evil men and the dissatisfaction with those who would do harm to the innocents, and giving thanks to G-d to be able to do something about it. That the souls of the wicked shall be purified by blood, and sent back to their maker, if it is in their power: In the name of the Father, and of the Son, and the Holy Spirit" The final part:

"In nomine Patris, et Filii, et Spiritus Sancti."

Means "In the name of the father, of the son, and the Holy Spirit" roughly.