Praise be to Allah.
The Muslim should hasten to do good deeds and compete with others in doing acts of worship, and this is emphasised even more during the month of Ramadan, in which the gates of Paradise are opened and the gates of Hell are closed, the devils are chained up and a caller calls out every night: O seeker of good, advance; O seeker of evil, go back.
Our advice to the one who misses some of the prayers without any excuse, or misses them because of something haraam, such as those who neglect the prayer in order to watch soap operas, is that they should be keen to offer the prayers with the Muslims and they should hasten to pray when they hear the adhaan (call to prayer). Ramadan is a month of worship and multiple reward; we ask Allah to protect us from the evil of our own selves and to help us to obey and worship Him, for He is the Most Munificent, Most Generous.
If some people have missed ‘Isha’ prayer with the regular imam, should they pray ‘Isha’ in congregation (jamaa‘ah), or should they join the imam in Taraweeh prayer, with the intention of praying ‘Isha’? That depends on their situation:
If they came in straight after the prayer, and there is enough time before Taraweeh to pray ‘Isha’, then in this case it is better for them to pray in jamaa‘ah on their own, so as to avoid differing with those scholars who do not allow a person to offer an obligatory prayer behind (an imam) who is offering a naafil prayer.
But if they came in whilst Taraweeh prayer was in progress, or the imam started to pray Taraweeh shortly after ‘Isha’, and there is the fear that if a second jamaa‘ah prays, the two groups will disturb one another, then in this case it is better to join the imam in Taraweeh, with the intention of praying ‘Isha’. Then when the imam says the tasleem after two rak‘ahs, they should stand up and complete the prayer by themselves.
Shaykh Ibn Baaz (may Allah have mercy on him) was asked: We notice that in some mosques, those who come after the end of ‘Isha’ prayer and the beginning of Taraweeh offer a second [‘Isha’] prayer, but by doing so they disturb those who are praying Taraweeh. Is it better for them to offer the prayer in jamaa‘ah, or to join the imam in Taraweeh prayer, with the intention of ‘Isha’? Is the ruling different if it is one person or a group that comes in?
He replied: If those who come in are two or more, then it is better for them to offer the prayer on their own – i.e., ‘Isha’ prayer – then to join the people in Taraweeh. But if they join the imam with the intention of praying ‘Isha’, then when the imam says the tasleem, each of them gets up and completes the prayer by himself, there is nothing wrong with that, because it was proven from Mu‘aadh (may Allah be pleased with him) that he used to pray the obligatory prayer of ‘Isha’ with the Prophet (blessings and peace of Allah be upon him), then he would go back to his people and lead them in offering that prayer; for him it was naafil but for them it was obligatory. But if only one person comes in, then it is better for him to join the imam with the intention of ‘Isha’, so that he will attain the virtue of praying in jamaa‘ah. Then when the imam says the tasleem following two rak‘ahs, he should complete ‘Isha’ by himself.
May Allah help us all to understand Islam properly.
End quote from Majmoo‘ Fataawa Ibn Baaz, 30/30
And Allah knows best.