[2:285] The Messenger believes in what was revealed to him from his Lord, and the believers; each one believes in God and His angels, and in His Books, and His messengers, 'we make no distinction between any of His messengers'. And they say, 'We hear and obey; Your forgiveness, our Lord; to You is the homecoming'.
This is the testimony of faith (shahāda) of the Real (s) on behalf of His Prophet (ṣʿa) and that is more perfect for him than his speaking for himself.
It is said all creatures believe through demonstrative proof (burhān) while the Messenger (ʿa) believes through eye-witnessing (ʿiyān).
It is said creatures believe through intermediaries while Muḥammad (ṣ) believes without one.
It is said this was the address of the Real with him on the Night of the Miʿrāj indicating respect for [his] rank: He said, 'The Messenger believes', not 'You [Muḥammad] believe', just as one says to an important person, 'the Shaykh said...' rather than 'you said...'.
It is said both the Messenger and the believers believe in God, His angels, His books and His messengers, but what a difference between one faith and another! All believe through reasoning (istidlāl) but you, O Muḥammad, believe through communion (wiṣāl).