Malachi 2:7-9

For the priest's lips should keep knowledge, and they should seek the law at his mouth: for he is the messenger of the LORD of hosts. But ye are departed out of the way; ye have caused many to stumble at the law; ye have corrupted the covenant of Levi, saith the LORD of hosts. Therefore have I also made you contemptible and base before all the people, according as ye have not kept my ways, but have been partial in the law.