his imam concludes the prayer, he rises and performs the additional rak'ah. This is a clear analogy, with no difficulty in it.
If someone were to ask: Does this not contradict the Prophet’s ﷺ statement: “Whoever stands in prayer with the imam until he leaves will be recorded as having stood the whole night in prayer”? (1)
We reply: It does not contradict it, because the Prophet ﷺ did not say, “Whoever stands in prayer with the imam and leaves with him will be recorded as having stood the whole night in prayer.” Rather, he made the limit of standing in prayer the imam’s departure. Whoever adds to his imam’s prayer after the imam has concluded with the taslim has stood with him until he left.
It is disliked to offer voluntary prayers during it, but not to resume prayer in congregation thereafter. ..........
His statement, “It is disliked to offer voluntary prayers during it,” means that voluntary prayer between the tarawih prayers is disliked. This occurs in two ways:
The first is for a person to offer voluntary prayers while the people are praying. There is no doubt that this is disliked, because he separates himself from the congregation. How can you pray alone while the Muslims are praying in congregation?
If he says, “I have not prayed the obligatory prayer, and I wish to pray the isha prayer,”
we say: There is no objection. Join the imam in the tarawih prayer with the intention of the obligatory prayer—that is, with the intention of isha. When he concludes with the taslim, stand and perform two rak'ahs to complete the obligatory prayer—unless you are travelling, in which case conclude with him. Then join him in the tarawih prayer with the intention of the regular sunnah prayer after isha, if you are not travelling. Once you have prayed the regular sunnah prayer of isha, join him in the tarawih prayer. There is no harm in the imam and the congregant having different intentions; that is, it is permissible for the imam to intend a voluntary prayer while the congregant intends an obligatory prayer. This is what Imam Ahmad expressly stated: that a person may pray the isha prayer behind one who is praying tarawih.