Imam Ahmad recorded from a man among the Companions of the Prophet that the Messenger of Allah led them in Fajr prayer and recited Ar-Rum in the prayer, but he became confused in his recitation. He said:

«إِنَّهُ يَلْبِسُ عَلَيْنَا الْقُرْآنَ، فَإِنَّ أَقْوَامًا مِنْكُمْ يُصَلُّونَ مَعَنَا لَا يُحْسِنُونَ الْوُضُوءَ، فَمَنْ شَهِدَ مِنْكُمُ الصَّلَاةَ مَعَنَا فَلْيُحْسِنِ الْوُضُوء»

(We have become confused in our recitation of Qur'an, because some people among you are praying with us but they have not performed Wudu' properly. Whoever attends the prayer with us, let him perform Wudu' properly.) This has a Hasan chain of narration, the text itself is Hasan. It contains amazing information, that the Prophet was affected by the faulty Wudu' of some of those whom he was leading in prayer. This indicates that the prayer of the person who is praying in the congregation is connected to the prayer of the Imam. This is the end of the Tafsir of Surat Ar-Rum. Allah's is the praise and thanks.