According to Imam Moosa Kazim (a.s.)
a person who afraid of robbers and wild animals in a journey should write the following Dua on the back of the horse and by the order of the Almighty God he will be safe from their mischief.
لَا تَخَافُ دَرَكاً وَ لَا تَخْشٰى
LAA TAKHAAFO DARAKAN WA LAA TAKHSHAA.
Not fearing to be overtaken, nor being afraid
The reporter of this tradition states that once he was going with a group to Haj. A last a band of wild Arab surrounded the group and attacked them fiercely but he had written this ayat on the back of his horse and taking an oath on Almighty God. Who had made Muhammad (s.a.w.a.) His prophet and Hazrat Ali (a.s.) His Imam he reiterated that the Almighty God had made the robbers blind to his presence and they did not incur him with any loss.