It is narrated from Abdullah bin Shaqiq that he said: I asked Sayyidah Aishah (may Allah be pleased with her): Did the Messenger of Allah (peace and blessings be upon him) combine surahs? She said: Yes! He would combine (surahs) from the Mufassal.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2461