The similitude of mine and that of the Apostles before me is that of a person who built a house quite imposing and beautiful and he made it complete but for one brick in one of its corners. People began to walk round it, and the building pleased them and they would say: But for this brick your building would have been perfect. Muhammad ﷺ said: And I am that final brick. (Using translation from Muslim 2286b)
وَقَالَ أَبُو الْقَاسِمِ ﷺ مَثَلِي وَمَثَلُ الْأَنْبِيَاءِ مِنْ قَبْلِي كَمَثَلِ رَجُلٍ ابْتَنَى بُيُوتًا فَأَحْسَنَهَا وَأَكْمَلَهَا وَأَجْمَلَهَا إِلَّا مَوْضِعَ لَبِنَةٍ مِنْ زَاوِيَةٍ مِنْ زَوَايَاهَا فَجَعَلَ النَّاسُ يَطُوفُونَ وَيُعْجِبُهُمُ الْبُنْيَانُ فَيَقُولُونَ أَلَا وَضَعْتَ هَاهُنَا لَبِنَةً فَيَتِمُّ بُنْيَانُكَ فَقَالَ مُحَمَّدٌ النَّبِيُّ ﷺ فَكُنْتُ أَنَا اللَّبِنَةَ