The Messenger of Allah ﷺ said, "My example and the example of the prophets before me is like that of a man who built a house, making it beautiful and complete except for the place of a single brick in one corner. People began going around it admiring it and saying, 'Why has this brick not been placed?' I am that brick, and I am the seal of the prophets."
أن رسول الله ﷺ قال: إن مثلي ومثل الأنبياء من قبلي، كمثل رجل بنى بيتا فأحسنه وأجمله إلا موضع لبنة من زاوية، فجعل الناس يطوفون به ويعجبون له، ويقولون: هلا وضعت هذه اللبنة؟ قال: وأنا اللبنة، وأنا خاتم النبيين.
Bukhari narrated it in the Book of Virtues (3535), and Muslim in the Book of Merits (2286:22), both from Qutayba bin Saeed, who said, "Ismail bin Jafar told us, from Abdullah bin Dinar, from Abu Salih, from Abu Hurairah," and he related it.