The Prophet ﷺ recited what he was commanded to recite, and remained silent regarding what he was commanded to keep silent about. "And your Lord is never forgetful" [Maryam 19:64]. "Indeed, in the Messenger of Allah you have an excellent example" [Ahzab 33:21].
قرأ النبي ﷺ فيما أمر، وسكت فيما أمر. {وما كان ربك نسيا}٦٤ [مريم: ٦٤]. {لقد كان لكم في رسول الله أسوة حسنة} [الأحزاب ٢١].
Bukhari narrated it in the chapter on adhan (774) from Musaddad, who said, Ismail told us, who said, Ayub told us, from Ikrima, from Ibn Abbas, who mentioned it. Ismail here is Ibn Ibrahim, known as Ibn Ulaya.His saying, "regarding what he was commanded," means whether to recite it aloud or silently. His saying, "and he was silent," means he recited it silently."And your Lord was never forgetful" [Kahf 18:64], regarding the omission of stating the details of the prayer in the Quran, whether recited aloud or silently, and other particulars of the prayer.Khattabi said, "The meaning of the Almighty's saying, 'And your Lord was never forgetful' [Kahf 18:64], and its application here, is that if He had willed to reveal a statement describing the actions, words, and forms of the prayer so that it would become recited Quran, He would have done so, and He did not omit that out of forgetfulness. Rather, He entrusted the explanation of that matter to His Messenger, then commanded that he be followed and that his actions be emulated. That is the meaning of His saying, 'that you may make clear to the people what has been sent down to them' [Nahl 16:44]." End of quote. Alam Hadith (1/502). See also Fath al-Bari (2/254).