Hadith 8116

وَقَالَ أَبُو الْقَاسِمِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ : " مَثَلِي وَمَثَلُ الْأَنْبِيَاءِ مِنْ قَبْلِي كَمَثَلِ رَجُلٍ ابْتَنَى بُيُوتًا ، فَأَحْسَنَهَا وَأَكْمَلَهَا وَأَجْمَلَهَا إِلَّا مَوْضِعَ لَبِنَةٍ مِنْ زَاوِيَةٍ مِنْ زَوَايَاهَا ، فَجَعَلَ النَّاسُ يَطُوفُونَ ، وَيُعْجِبُهُمْ الْبُنْيَانُ ، فَيَقُولُونَ : أَلَا وَضَعْتَ هَاهُنَا لَبِنَةً ، فَيَتِمُّ بُنْيَانُكَ " فَقَالَ مُحَمَّدٌ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ : " فَكُنْتُ أَنَا اللَّبِنَةَ " .
And the Prophet Muhammad (peace and blessings be upon him) said: My example and the example of the prophets before me is like that of a man who built a very beautiful and complete building, except that he left a space for one brick in one of its corners. People would walk around it, marvel at it, and say: We have never seen a building more splendid than this, except for the place of that brick. So I am that brick.
Hadith Reference مسند احمد / مسند المكثرين من الصحابة / 8116
Hadith Grading حکم دارالسلام: إسناده صحيح، خ: 3535، م: 2286