What is the virtue of performing the night vigil (qiyam al-layl) specifically by reciting Surat Ar-Rahman and Surat Al-Mulk?

There is no authentic hadith specifying the virtue of reciting Surah Ar-Rahman and Surah Al-Mulk during Qiyam al-Layl (night vigil prayer). Weak hadiths have been reported regarding the virtue of Surah Ar-Rahman, while authentic hadiths have been reported regarding the virtue of Surah Al-Mulk.