There is no objection to combining surahs in a single rak'ah

Question:
We return at the beginning of this episode to a message sent to the program from al-Ta'if, from the listener A-M-S, a Sudanese. We presented some of his questions in a previous meeting, and in this meeting he asks your eminence, Shaykh Salih, and says: In the regular voluntary prayers (rawatib), the Prophet (peace and blessings be upon him) used to recite after al-Fatihah Surat al-Kafirun and al-Ikhlas. Sometimes I recite the Verse of the Throne, then I recite Surat al-Kafirun after it in the first rak'ah, then I recite al-Ikhlas after it in the second rak'ah. Is my practice correct? Please guide me, may Allah reward you with good.

Answer:
There is no objection to combining surahs in a single rak'ah, but adhering to specific surahs, as the questioner mentioned, and persisting in doing so is not permissible, because it requires evidence, and there is no evidence for adhering to these surahs and persisting in them. So he should leave this habit and recite whatever is easy for him of the Qur'an and the surahs, and not adhere to specific surahs except what is reported from the Messenger (peace and blessings be upon him) that he used to recite them in the witr, in the qunut, in the odd and even rak'ahs. He used to recite (peace and blessings be upon him) in the first rak'ah of the night prayer, "Subhan bi-smi Rabbika al-A'la" (Glory be to your Lord, the Most High).
In the second rak'ah, "Qul ya ayyuha al-kafirun" (Say, O disbelievers). And in the third rak'ah, Surat al-Ikhlas. Likewise, he (peace and blessings be upon him) used to recite in the two rak'ahs of Fajr, the two rak'ahs of tawaf, "Ya ayyuha al-kafirun" in the first rak'ah, and al-Ikhlas in the second rak'ah. And sometimes he would recite to us in the first rak'ah from Surat al-Baqarah, and in the second rak'ah from Surat al-Imran. And likewise, he used to recite in the Fajr prayer on Friday, "Alam Tanzil" (The Surah of Prostration) in the first rak'ah, and "Hal Atat 'Ala al-Insan" (Has There Come Upon Man) in the second rak'ah. And in the Friday prayer, the Prophet (peace and blessings be upon him) would sometimes recite "Sabbih" and "Al-Ghashiyah," and sometimes recite Surat al-Jumu'ah and al-Munafiqun. These are the surahs that the Prophet (peace and blessings be upon him) used to recite in these prayers most of the time.
As for specifying surahs other than what is reported from the Messenger (peace and blessings be upon him) in those circumstances, this is considered a religious innovation (bid'ah). Yes.