I don't know of any documented reason; hadjust assumed her name followed a pattern seen fairly often among Pilgrims, Quakers and other such communities of the period. Giving Biblical names and naming children after virtues thought of as Christian, were popular trends among such folk. "Silence" was golden, was it not?
Would love to know more about the New Jersey branch of the Brockett-Penningtons. Am still pretty new at this delving into genealogy myself, but am having lots of fun with it. Happy searching!