Prayers that is equivalent to spending the whole night in prayer.
One of the imams stated that it is essential to complete Tarawīh prayer with the imam and not to leave halfway through, because what you have done with him, whether it is two raka’at or four, will not count for you. Is this correct?
In the name of Allāh, Most Gracious, Most Merciful;
All the praise and thanks is due to Allāh. Peace and blessings be upon His Messenger.
It is undoubtedly incorrect for the imam to hold the view that it is essential to complete Salāt al-Tarawīh with the imām and not to leave halfway through because what you have done with him will not be counted. Such an action is not permissible for anyone to attribute to something that is not part of it. Allāh has forbidden us to speak of Him without knowledge, as He says:
“Say (O Muhammad): (But) the things that my Lord has indeed forbidden are al Fawāhish (great evil sins and every kind of unlawful sexual intercourse) whether committed openly or secretly, sins (of all kinds), unrighteous oppression, joining partners (in worship) with Allāh for which He has given no authority, and saying things about Allāh of which you have no knowledge”
But it is whoever stands with the imām until he has completed Salāt al-Tarawīh; it is equivalent to spending the whole night in prayer.
The hadith was narrated that Abu Dharr (radiallāhu`anhu) said: The Messenger of Allāh (Sallallāhu `alayhi wa sallam) said:
“Whoever stands with the imam until he concludes, it is equivalent to spending the whole night in prayer.”
[Narrated by al-Tirmidzi, 806; Abu Dawud, 1375; al-Nasa’ie, 1605; Ibn Majah, 1327; Classified as sahih by al-Tirmidzi, Ibn Khuzaymah (3/337), Ibn Hibban (3/340) and al-Albani in Irwa’ al-Ghalil, 447]
This reward (the reward of spending the whole night in prayer) is not attained by anyone except the one who stands with the imam for the whole prayer, until he completes it, as the Prophet (Sallallāhu `alayhi wa sallam) said.
As for the one who prays as much as he can and then leaves before the imam has completed his prayer, only what he has prayed will be recorded for him, but it will not be recorded as if he spent the entire night in prayer.
“So whosoever does good equal to the weight of an atom (or a small ant) shall see it. And whosoever does evil equal to the weight of an atom (or a small ant) shall see it”
And Allāh knows best.
[Excerpted from Islam Q&A (65501)]