The greatest enmity is that which is done to the one who is rightfully to be ascribed with Magnitude because it’s from His right that He be singled out in worship in belief, actions, and speech because that is His right upon the creation.
It’s mentioned in the hadeeth: The Prophet ﷺ said:
أَنْ يَعْبُدُوهُ وَلَا يُشْرِكُوا بِهِ شَيْئًا
To worship Him alone and to associate none in worship with Him.[ Reported by Bukhari]
Excerpted from Shirk According to Scholars From The Four Madhhabs. By Shaykh Dr Muhammad al-Khumayyis Trans: By Abdul Haq Al-Ashanti