It is narrated from Hazrat Asim bin Umar that he says Hazrat Umar (may Allah be pleased with him) used to say: Allah Almighty protects the believer. Hazrat Asim bin Thabit bin Aflah had vowed that he would not touch any polytheist, nor would any polytheist touch him. Thus, just as he avoided this during his life, in the same way Allah Almighty protected him from it after his death as well.