Ruling on performing the night prayer consecutively with the witr without a break between them

From Sa'd Sa'ud ibn Sulayman in Riyadh. We received this message regarding the sunnah that comes after the 'Isha' prayer. He says: If I pray the rawatib after the 'Isha' prayer, then I stand and pray the shaf', and then I perform the witr afterwards without sitting for the tashahhud, is that permissible or not?
The Shaykh: It seems he wants to say that he prayed the shaf' and the witr together?
The presenter: Yes, yes.
The Shaykh: Meaning, performing the three consecutively?
The presenter: Yes.
Answer: If a person prays the rawatib of 'Isha', then stands and prays three units consecutively without sitting, there is no harm. It has been reported from the Prophet (peace and blessings be upon him) that he did this on some occasions. He would perform the witr with three units and not say the taslim until the end of them, (peace and blessings be upon him). This is a type of sunnah and there is no harm in it. However, it is disliked to sit in the second unit, complete it, and then stand up without saying the taslim, like in the Maghrib prayer. No, this is disliked. Rather, either he says the taslim after the two units, which is better, and then performs one unit alone, separate. This is the best, and it is the most common of the actions of the Prophet (peace and blessings be upon him). And if he performs them consecutively without sitting in the second unit, performing them consecutively and then saying the taslim in the third unit, there is no harm in that. The Prophet (peace and blessings be upon him) did this. But the many authentic hadiths state that he would say the taslim after the two units, then stand and perform the witr unit alone. This is the best, and this is the most common of the actions of the Prophet (peace and blessings be upon him). Yes.
The presenter: But Your Eminence, if he forgets and stands in the second unit or after the second unit, does he prostrate for forgetfulness or ...?
The Shaykh: Was he intending?
The presenter: Yes, he wants to perform the witr ...
The Shaykh: If he intended to sit in the two units, then he forgot and stood up, the best is that he returns. The best is that he returns, sits, completes it, and prostrates for forgetfulness. Then he performs the one unit alone, the witr unit alone. Because the Messenger (peace and blessings be upon him) said: . So if he did not intend to perform the three consecutively, then if he stands up, he sits. He sits, performs the tashahhud, completes his tashahhud and makes his supplication, then he prostrates two prostrations for forgetfulness, then he says the taslim, then he stands and performs the one unit, which is the witr.
As for if he intended to perform the three consecutively, there is no harm on him. It is established from him (peace and blessings be upon him) that he performed three units consecutively, and performed five units consecutively, without sitting except at the end, (peace and blessings be upon him). And it is established from him that he performed seven units consecutively, sat in the sixth, performed the tashahhud, then stood up without saying the taslim, then he performed the seventh, performed the tashahhud, and said the taslim. And it is established from him that he prayed nine units consecutively, sat in the eighth, performed the tashahhud, and did not say the taslim, then he stood and performed the ninth. All of this is established from his actions (peace and blessings be upon him). But the best, the most common, and the most frequent of his actions (peace and blessings be upon him) is that he would say the taslim after every two units, as he said (peace and blessings be upon him): . And A'ishah (may Allah be pleased with her) said: . This is the best, and this is the most common of the actions of the Prophet (peace and blessings be upon him). But if someone performs three units consecutively and does not sit except in the third, or five units and does not sit except in the fifth, there is no harm on him. Because the Messenger did this on some occasions (peace and blessings be upon him). And likewise, if he performs seven units consecutively, sits in the sixth, performs the tashahhud, and does not say the taslim, then stands for the seventh, or performs nine units consecutively, sits in the eighth, performs the tashahhud, and does not say the taslim, then stands and performs the ninth, this is also permissible. Both are authentic from the Prophet (peace and blessings be upon him), so there is no harm in that.
The presenter: May Allah reward you!