It is narrated from Ibn Abi Mulaykah that the people of Iraq wrote to Ibn al-Zubayr (may Allah be pleased with him), asking him about the grandfather. Ibn al-Zubayr (may Allah be pleased with him) said: The one about whom the Messenger of Allah (peace and blessings be upon him) said, "If I were to take anyone as a khalil, I would take Abu Bakr as a khalil," he (Abu Bakr, may Allah be pleased with him) declared the grandfather to be like the father.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12419