Abdullah bin Abu Mulayka reported,

The people of Kufa wrote to Ibn Zubayr asking about the grandfather's share of inheritance. He replied, "As for the one about whom the Messenger of Allah ﷺ said, 'Had I taken anyone from this nation as a close friend, I would have taken him,' he treated him as a father," meaning Abu Bakr.

Azami 9835

Sahih

عن عبد الله بن أبي مليكة قال

كتب أهل الكوفة إلى ابن الزبير في الجد، فقال: أما الذي قال رسول الله ﷺ: لو كنت متخذا من هذه الأمة خليلا لاتخذته أنزله أبا، يعني أبا بكر.

الأعظمي 9835صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Virtues of the Companions and reports about them
Chapter
Virtues of Abu Bakr and his reports
Section
If the Prophet ﷺ had taken a close friend, it would have been Abu Bakr
Numbering
Jami al-Kamil 9835 (2nd edition)
Azami 9835