Pooh pooh pooh!
The protective power of metal also can be derived from the biblical discussion of the first plague, in which God states that all water stored "in vessels of wood and stone" (Exod. 7:19) will turn to blood. According to this, metal receptacles are not mentioned because they must have protected the water from changing. Another explanation is that metal means luck, since "barzel" (the Hebrew word for iron) is an acronym for the names of four of the mothers of the Children of Israel (Bilhah, Rachel, Zilpah, and Leah), who could ward off all dangers to their progeny.
Knocking on Wood
Knocking on wood to protect from evil is a non-Jewish practice, even though many Jews do it. Many connect this action to Christian beliefs that relate wood to slivers of the cross, which were believed to bring good luck. However, this practice has a more universal, pantheistic origin. Long before the time of Jesus, some cultures regarded trees as gods; believers were convinced that touching (or knocking on) wood could produce magical results.
Did you like this article? MyJewishLearning is a not-for-profit organization.