"And We removed from you your burden." The burden (al-wizr) is the load, and it refers to the sins that were upon him during the Era of Ignorance (Jahiliyyah).
﴿ووضعنا عَنْك وزرك﴾ الْوِزْرُ: الْحِمْلُ، وَهِيَ الذُّنُوبُ الَّتِي كَانَت عَلَيْهِ فِي الْجَاهِلِيَّة
