hale says "they the books must be heavy , they are weighted with authority" what is the significance of the remark

Hale brings all his precious witch books to town. He seems to have complete trust in them,

"Here are all your familiar spirits- your incubi and succubi; your witches that go by land, by air, and by sea; your wizards of the night and of the day."

THey are physically heavy but Hale also feels they are weighted with God's justice upon the wicked and His mercy upon the pure.