"Say, 'For me is my work, and for you is your work,'" meaning: you are not responsible for any part of my work, and I am not responsible for any part of your work.
﴿فَقُلْ لِي عَمَلِي وَلَكُمْ عَمَلُكُمْ﴾ أَيْ: لَيْسَ عَلَيْكُمْ مِنْ عَمَلِي شَيْءٌ، وَلَيْسَ لِي مِنْ عَمَلِكُمْ شيءٌ.
