Urwah bin Udhaynah said: I set out with my grandmother, who had vowed to perform Hajj on foot. When we had gone some way along the road, she became unable to walk. She sent her slave to Abdullah bin Umar (may Allah be pleased with them both) to ask him, and I went along too. He said: Tell her to ride, and then to walk from the point where she became unable.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النذور / 20128