In the Name of Allah, the Most Gracious, the Most Merciful.
The companions of the Prophet (peace be upon him) differed in matters of understanding, yet their hearts were united. After the Prophet's death, when the news reached them that the people of Yemen had accepted Islam, he appointed Mu'adh ibn Jabal as governor and judge. The Prophet asked him: "By what will you judge?" He said: "By the Book of Allah." He asked: "If you do not find it there?" He said: "By the Sunnah of the Messenger of Allah." He asked: "If you do not find it there?" He said: "I will strive with my own judgement." The Prophet approved.
This is the adab of disagreement: to refer first to the Book and the Sunnah, and where they leave room for understanding, to strive sincerely while respecting the striving of others.
The early scholars embodied this. Imam Malik was asked about a matter, and he would often say: "I do not know." When he did give an answer, he would say: "This is my opinion, and it may be wrong." Contrast this with the certainty of the layman who has read a single article.
Imam al-Shafi'i would change his rulings when he travelled to a new land, recognizing that the circumstances of the people demanded a different application of the same principles. He did not accuse his earlier self of heresy; he acknowledged that knowledge grows with exposure.
The adab of disagreement is not weakness. It is the natural fruit of reverence for Allah and for His religion. The one who fears Allah does not speak in His name without knowledge, and the one who loves the believers does not accuse them without proof.
May Allah make us among those who speak the truth with mercy, and who are silent with wisdom.