Knock On Wood

A classic 1966 Stax Records 45 by Eddie Floyd, who was, once, in The Falcons; co-written by Floyd and Steve Cropper. It utilized the "Midnight Hour" beat (good for doing The Jerk, IIRC) and Stax sat on the recording (done in '65) due to that and other similarities. Later covered, sans all subtlety, using a discoSTOMP beat, sound FX, and a singer-for-hire named Amii Stewart. A punk version, from about the same time, lost a lot in the loudFAST translation.

What is the origin of the action of knocking on wood?

To knock on wood is a superstitious action to ward off any evil consequences, say of boasting; it can also be a charm to bring good luck. The exact origin is unknown, although some writers and historians have pointed to pre-Christian rituals involving the spirits of sacred trees such as the oak, ash, holly or hawthorn. There is an old Irish belief that you should knock on wood to let the little people know that you are thinking them for a bit of good luck (although at this time, the little people were unavailable for comment).

Others have sought a meaning in which the wood symbolizes the timber of the cross, but this may be a Christianization of an older ritual. The phrase itself seems to be modern, as the oldest citation for, "knock on wood," is, "touch wood," as found in the Oxford English Dictionary dates back only to 1908.