Ibn Abi Mulaykah (may Allah have mercy on him) said that Sayyiduna Abdullah bin al-Zubayr (may Allah be pleased with him) wrote to the people of Iraq: The one about whom the Messenger of Allah (peace and blessings be upon him) had said, "If I were to take anyone besides Allah as an intimate friend until I meet Allah, I would have taken Abu Bakr as an intimate friend" - he (Abu Bakr, may Allah be pleased with him) used to count the grandfather as having the ruling of a father.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13870