Ruling on performing voluntary prayer with more than two units in one closing salam

Question:
Is it permissible to perform voluntary prayer in the manner of the obligatory prayer: for example, praying four units before the afternoon prayer in the manner of the obligatory prayer, meaning with two sittings for the testimony and one closing salam, or with one sitting for the testimony, whether that is at night or during the day? We ask that you mention the evidence for the permissibility or the prohibition.

Answer:
What is prescribed for the believer is to pray two units at a time, at night and during the day. This is how the Prophet (peace and blessings be upon him) used to do it. He (peace and blessings be upon him) said: It is agreed upon that it is authentic. In the other wording, he said: It was narrated by Imam Ahmad and the people of the Sunan with an authentic chain. Thus, he mentioned both night and day. His custom (peace and blessings be upon him) was to pray two units at a time, at night and during the day. This is what is prescribed.
Some scholars have permitted praying four units all together during the day. However, the correct position, and what the Sunnah indicates, is that voluntary prayer is performed two units at a time, two units at a time, at night and during the day. This is what is prescribed. At night, it is not permissible [to pray four units with one salam]; because the hadiths are established and have no defect: It is agreed upon that it is authentic. However, it is permissible at night to pray three units with one closing salam and one sitting, and it is permissible to pray five units with one sitting and one closing salam, there is no harm in that, as witr. As for praying four units all together, or six units all together, or eight units all together and then closing the prayer from them; this has not come in the Sunnah.
The believer should adhere to the Sunnah and pray two units at a time, except when he performs witr with three, five, seven, or nine units all together, there is no harm in that, as the Prophet (peace and blessings be upon him) did. But if he performs witr with seven units, he sits in the sixth unit and recites the first testimony, then stands up for the seventh unit. And if he performs witr with nine units, he sits in the eighth unit for the first testimony, and stands up for the ninth unit. This came specifically regarding witr. And if he prays the seven units like the five units and does not sit except in the last one, there is no harm. This and that came from the Prophet (peace and blessings be upon him).