31. And when they had prayed. Luke declareth now that God did not only hear this prayer, but did also testify the same by a visible sign from heaven. For the shaking of the place should, of itself, have done them small good; but it tendeth to another end, that the faithful may know that God is present with them. Finally, it is nothing else but a token of the presence of God. But the fruit followeth, for they are all filled with the Holy Ghost, and endowed with greater boldness. We ought rather to stand upon this second member. For whereas God did declare his power then by shaking the place it was a rare and extraordinary thing; and whereas it appeared by the effect, that the apostles did obtain that which they desired, this is a perpetual profit of prayer, which is also set before us for an example.