Abu Dawud

Benefits and Issues:
To combine Allah and His Messenger sallallahu alayhi wa sallam in a single word or with a dual pronoun, such as saying: (wa man ya'sihuma) "whoever disobeys both of them," is considered contrary to proper etiquette.
They should be mentioned separately, such as by saying (wa rasuluhu) "and His Messenger."

“You are a bad preacher.” Your (the Prophet’s) indication is towards combining Allah and His Messenger in a single pronoun (the “himā” in “yaʿṣihimā”). As is explicitly mentioned in the narration of Sahih Muslim, you (sallallahu alayhi wa sallam) had said: [وَمَنْ يَعْصِ اللَّهَ وَرَسُولَهُ ] “Whoever disobeys Allah and His Messenger (sallallahu alayhi wa sallam).” (Sahih Muslim, al-Jumuʿah, Hadith: 870) Similarly, in one of your sermons, these exact words are found: [ومن يعصِهِما فإنَّه لا يضرُّ إلّا نفسَهُ ] (Sunan Abi Dawud, al-Salat, Hadith: 1097) Also, in the Noble Qur’an: ﴿إِنَّ اللَّهَ وَمَلائِكَتَهُ يُصَلُّونَ﴾, there is also a shared pronoun, yet here you expressed displeasure at the use of the dual pronoun. The reason for this is that, in the context of admonition and speech, there is a need for clarity and explanation rather than ambiguity. This preacher demonstrated ambiguity here, which you did not approve of. From this, it is understood that although brevity is not impermissible, when addressing the general public, one should speak in clear words rather than in brief terms, even if it results in some length, so that the public does not fall into misunderstanding. See also: (Sharh Sahih Muslim by al-Nawawi, Hadith: 870)

1099. Commentary:
The Prophet sallallahu alayhi wa sallam did not approve of mentioning Allah and His Messenger together using a dual pronoun; this is contrary to proper etiquette. There is a possibility of implying equality in this. If this meaning needs to be conveyed, then «من يعص الله ورسوله» should be said.