It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that a man asked the Prophet (peace and blessings be upon him) about throwing the pebbles (rami al-jimar): "What (reward) is there in it for us?" Then I heard him (peace and blessings be upon him) say: "You will find it with your Lord at the time when you are most in need of it."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from al-Qasim bin Abi Bazzah except Hajjaj, and no one narrated it from Hajjaj except Abd al-Salam; Abd al-Mu'min is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب العين / 4147
Hadith Gradingمحدثین:فيه الحجاج بن أرطاة وفيه كلام
Hadith Takhrij«قال الهيثمي: وفيه الحجاج بن أرطاة وفيه كلام «مجمع الزوائد ومنبع الفوائد، ج 3، ص 260»» «أخرجه الطبراني فى «الكبير» برقم: 13479»