What is the meaning of Verner's law?

A statement, propounded by the Danish philologist Karl Verner in 1875, which explains certain apparent exceptions to Grimm's law by the original position of the accent. Primitive Indo-European k, t, p, became first in Teutonic h, th, f, and appear without further change in old Teutonic, if the accent rested on the preceding syllable; but these sounds became voiced and produced g, d, b, if the accent was originally on a different syllable. Similarly s either remained unchanged or it became z and later r. Example: Skt. sapta (accent on ultima), Gr. 'e`pta, Gothic sibun (seven). Examples in English are dead by the side of death, to rise and to rear.