My example and the example of the prophets before me is like a man who built houses, making them excellent, complete, and beautiful, except for the place of one brick in one of their corners. People began walking around the buildings, marveling at the construction, saying, "If only a brick had been placed here, your building would be complete." Muhammad the Prophet ﷺ said, "So I was that brick."
مثلي ومثل الأنبياء من قبلي كمثل رجل ابتنى بيوتا فأحسنها وأكملها وأجملها إلا موضع لبنة من زاوية من زواياها فجعل الناس يطوفون ويعجبهم البنيان فيقولون ألا وضعت هاهنا لبنة فيتم بنيانك فقال محمد النبي ﷺ فكنت أنا اللبنة
This is a sahih hadith. It is found in the Isolated Manuscript, number 2. Muslim [7:64s/2:206-207 Bulaq] narrated it from Muhammad bin Rafi from Abdul-Razzaq. Something similar to it has already appeared at 7318m3 from the recension of Aaraj, and it also appeared at 7479 from the narration of Musa bin Yasar from Abu Hurairah. Bukhari did not narrate it from the manuscript of Hammam. He only narrated it at [6:408 Fath] from the narration of Abu Salih from Abu Hurairah, as we explained there.