The significant difference between disagreement and valid disagreement 

Many people say "there is no denial in matters of disagreement," but this statement is not correct. There is no denial in matters of valid disagreement "Ijtihad." Ibn Taymiyyah said, "The idea that there is no denial in matters of disagreement is not correct. Denial is either directed towards a ruling or an action. If the statement contradicts the Sunnah or an ancient consensus, then it must be denied in accordance with the severity of the contradiction. As for action, if it goes against the Sunnah or consensus, it must also be denied according to the severity of the contradiction.

If there is neither Sunnah nor consensus in a matter and there is room for valid disagreement, then there is no denial for one who acts upon it, whether striving or following. The confusion arises from the belief that matters of disagreement are matters of valid disagreement "Ijtihad," as some people think. The correct stance, according to the imams, is that matters of valid disagreement "Ijtihad" must be followed if there is no evidence to the contrary, such as an authentic hadith with no opposing evidence of its kind. If there is no evidence, then it is necessary to clarify the invalidity of the analysis. Sheikh Ibn Uthaymeen said in response to those who said, "There is no denial in matters of disagreement," that if we were to say, "There is absolutely no denial in matters of disagreement," then the entire religion would be lost as people would follow their own desires, leading to widespread disagreement. Matters of disagreement are divided into two categories: those suitable for valid disagreement "ijtihad" and those not suitable for it, for which denial is necessary. Ibn Uthaymeen's words explain that the public must follow the scholars of their country in order to avoid widespread deviation. Sheikh Abdul Rahman bin Saadi said, "The common people must follow the scholars of their time." The second category of disagreement has no room for valid disagreement "ijtihad," and denial is necessary because there is no excuse.