For if once a man indulges himself in murder, very soon he comes to think little of robbing; and from robbing he comes next to drinking and Sabbath-breaking, and from that to incivility and procrastination. Once begin upon this downward path, you never know where to stop. Many a man has dated his ruin from some murder or other that perhaps he thought little of the time.

Thomas De Quincey (1785-1859) English writer, essayist, literary critic

Essay (1839-11), “Second Paper on Murder Considered as One of the Fine Arts,” Blackwood’s Edinburgh Magazine, Vol. 46, No. 289
    (Source)