What the Bible says about Challenging Authority of Moses
(From Forerunner Commentary)

Numbers 12:5-9 They were very severely rebuked for challenging the authority or the office of Moses because they were tempting God by doing it. They were in effect saying, "God can't control Moses. He's off doing his own thing." They were really calling God into account for what Moses was doing, which they thought was wrong. Nevertheless, Moses was still the one that God was working through. John W. Ritenbaugh Unity (Part 2): God's Pattern of Leadership Related Topics: Tempting God