Is a Muslim's wrongdoing against another Muslim more severe and graver than slandering and cursing the Messenger of Allah, peace and blessings be upon him, or his Companions and wives?

No tribulation descends except due to a sin, and none is lifted except by repentance. Oppressing and harming a Muslim are among the greatest sins, and the worst of them is oppressing the companions of the Prophet, peace and blessings be upon him. Cursing the Prophet, peace and blessings be upon him, is disbelief that expels its perpetrator from the fold of Islam; whoever does it is cursed in this world and the Hereafter, and their blood is forfeit. One must repent and turn to Allah Almighty, for calamities are due to what one's hands have earned.