An incident during the period of India's partition....
The road leading into Delhi was utterly unsafe and extremely dangerous (for Muslims). No one had the courage to go there. May Allah reward our Haji Babu Ayaz Saheb, and grant him even more courage. At that time, in spite of the extreme danger, he used to go there to fetch the dire rations. He brought rations for fifteen men, while there were about five hundred people staying in the Musjid. However, these rations were very helpful for the children. Everyone was quite dumb-struck at his courage in going to bring these rations. Once he was bringing some rations from Sabzi Mandi (market- place), on the way back he was in a tanga together with one Hindu and three sikhs. As they left Delhi the Sikhs told him: "How is it that you come to sit right in our midst? If we should kill you, then what?" He replied loudly and without fear: 'You will never be able to kill me, if you are brave enough, then take courage and do it."
When he said that they hesitated, started thinking and even looking at each other, they even made some signs to each other. Then rolling up their sleeves, they asked: "And why can we not He replied with even more fervour: "Because I have such a thing with me which makes it impossible for you to kill me." Through Allah's Grace they became so frightened, that right up to Nizamuddin, they continued thinking and making signs to each other. At the time of his getting out of the tanga at Nizamuddin, the Hindu asked: "Show me that thing." He replied: "No sir, this thing is not to be shown or seen." When I asked him what the thing was, he replied: "You should know, because you taught us one dua:
اللَّھُمَّ اِنَّا نَجْعَلُكَ فِي نُحُورِھِمْ وَ نَعُوذُبِكَ مِنْ شُرُورِھِمْ
"Allahuma inna naj'aluka fi nuhurihim wa na'oozobika min shuroorihim" "
O Allah we place You upon their necks and we seek refuge in You from their evil."
I started thinking: This 'thing' had not been shown to them and yet it had such an effect upon them. There is absolutely no doubt that there is great effect in the words of Allah; on condition that we are of true Imaan. I have already written previously that my uncle once gave me a dua to be read over a certain person and to blow over him afterwards. He further even said: "And if he does not recover, then it will be better for him if he dies." I have had endless experiences of this from the duos in the Hadith. If Allah should now again grant me the faith and yaqeen in Him, that I had at that critical time, it will be a great favour to me.
From Aap Beti Vol 4-5