A person who combined Maghrib and 'Isha', and when the time for 'Isha arrived, he went to the mosque and joined the congregation as a voluntary act

The questioner: By Allah - our professor - regarding a person who combined Maghrib and 'Isha, and when the time for 'Isha arrived, he went to the mosque and prayed voluntarily, praying with the standing congregation. Does this voluntary prayer count as part of...? Of course, we have heard the hadith that says: "The Messenger of Allah did not exceed eleven or thirteen rak'ahs after 'Isha." Do these four rak'ahs count as part of the thirteen rak'ahs, and then can I - for example - as we also hear that the night prayer is prayed in pairs of two, can I separate between two rak'ahs and two rak'ahs while I am behind the imam?

The Shaykh: Is this a second question or what?

The questioner: I mean, it is all intertwined.

The Shaykh: Do not intertwine them; because knowledge requires clarification and explanation. So, is this a second question? Do we consider it as such?

The questioner: Yes.

The Shaykh: This person who prayed 'Isha a second time with the congregation in the mosque, this is considered an absolute voluntary prayer for him, and it has no connection to the night prayer. In other words, if this man has a good habit of praying at night, either in the first part of the night, or in the middle, or in the last part, according to his energy and free time, then if he wants to pray, he prays eleven rak'ahs, and he does not count the four rak'ahs he prayed behind the congregation as the second prayer of 'Isha. If we are done with the answer to the first question, I am now ready to understand your second question well. What is it? Does he pray four by four, or two by two?

The questioner: Of course, as we know that the night prayer is in pairs of two; and since the first question has been clarified, but please, it is possible to...

The Shaykh: Therefore, then nothing is intertwined!!

Another questioner : ... .
First: As you know, . Second: He intended to pray voluntarily, and it was because he caught the second congregation, like the two men whose story we mention in the Prophet's (peace be upon him) Farewell Pilgrimage. He (peace and blessings be upon him) prayed the Fajr prayer in the Mosque of Mina, the Mosque of al-Khayf, and when he finished the Fajr prayer, he found two men in a place far from the mosque, so he called them and said to them: They said: Yes, O Messenger of Allah. He said: . They said: O Messenger of Allah, we had prayed in our tents. He said: . So this is a voluntary prayer. Repeating the obligatory prayer that he prayed because of his attendance at the congregation is considered an absolute voluntary prayer, whereas the night prayer is not like that.
The questioner : Yes, I do.