It is characteristic of the American “man in the street” that he displays very little reverence for the purity or tradition of his language.
If he can coin a new, catchy phrase, or twist an old one into a new meaning, he delights in so doing.
Thus, early in the nineteenth century someone, just who is not known, observed that the singing of the doxology always meant that his church service was finished.
Mental play with “doxology” revealed that reversal of the consonant sounds of the first and second syllables gave him “sock-dology.”
The similarity to sock, “a blow,” was obvious, and forthwith was born the sockdologer, the mighty blow that was to the battle as the doxology was to the service, the finish.