This staff was a sign of evil because of its reference in the Adam and Eve story. A snake is what led Adam and Eve to their destruction from the Tree of Knowledge, which is similar to Goodman Brown because they both were seeking an unknowing understanding amount of knowledge. Once Adam and Eve ate the forbidden fruit from the Tree of Knowledge they were expelled from their paradise. Eventually, the Devil's staff will lead Goodman Brown to the Devil's ceremony, destroying his faith, and expelling him from his utopia.
However, Goodman Brown suspects something is wrong and no longer wants to continue his journey. But, the Devil is smart and will not let him quit so quickly. Goodman Brown proclaims he came from a "race of honest men and Christians" and that his father would have never gone on this journey. Needless to say, the Devil is quick to point out he was with his father and grandfather when they were flogging a woman or burning an Indian village (615). These acts were ironic because they were bad deeds done in good faith, but the Devil used them to convince Goodman Brown he did not come from "good Christians." This was a ploy to get Goodman Brown to lose his faith and follow the Devil.
Furthermore, Goodman Brown's first excuse to stop the journey was not convincing, so he tried again and the Devil pretended to buy it. Goodman Brown said he could not continue the journey because he did not want his wife Faith to come to any harm (616). The devil agreed he should turn back, but used the excuse against him. The Devil showed Goodman Brown the woman "who had taught his catechism in youth, and was still his moral and spiritual adviser" was on the journey (Hawthorne 616). This was ultimately the beginning of Goodman Brown's damaged faith. After the Devil and the woman talk, Goodman Brown continues to walk with the Devil in the disbelief of what he has just witnessed. Ironically, he blames the woman for conversing with the Devil but his pride stops him from realizing his own faults are the same as the woman's.