It was narrated that Ibn Abi Mulaikah said. It was said to Abu Bakr:

O khaleefah (caliph) of Allah. He said: I am the khaleefah (lit. successor) of the Messenger of Allah (ﷺ) and I am pleased with that.

حَدَّثَنَا مُوسَى بْنُ دَاوُدَ، حَدَّثَنَا نَافِعٌ يَعْنِي ابْنَ عُمَرَ، عَنْ ابْنِ أَبِي مُلَيْكَةَ، قَالَ قِيلَ لِأَبِي بَكْرٍ رَضِيَ اللَّهُ عَنْهُ يَا خَلِيفَةَ اللَّهِ فَقَالَ أَنَا خَلِيفَةُ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَأَنَا رَاضٍ بِهِ وَأَنَا رَاضٍ بِهِ وَأَنَا رَاضٍ‏.‏