Hadith: O people, pray at your homes, for a person’s best prayer is the one he performs at his home except the obligatory prayer

عن زيد بن ثابت رضي الله عنه أَنَّ النَّبِيَّ -صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ- اتَّخَذَ حُجْرَةً فِي المَسْجِدِ مِنْ حَصِيرٍ، فَصَلَّى رَسُولُ اللَّهِ -صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ- فِيهَا لَيَالِيَ حَتَّى اجْتَمَعَ إِلَيْهِ نَاسٌ، ثُمَّ فَقَدُوا صَوْتَهُ لَيْلَةً، فَظَنُّوا أَنَّهُ قَدْ نَامَ، فَجَعَلَ بَعْضُهُمْ يَتَنَحْنَحُ؛ لِيَخْرُجَ إِلَيْهِمْ، فَقَالَ: «مَا زَالَ بِكُمُ الَّذِي رَأَيْتُ مِنْ صَنِيعِكُمْ، حَتَّى خَشِيتُ أَنْ يُكْتَبَ عَلَيْكُمْ، وَلَوْ كُتِبَ عَلَيْكُمْ مَا قُمْتُمْ بِهِ، فَصَلُّوا أَيُّهَا النَّاسُ فِي بُيُوتِكُمْ، فَإِنَّ أَفْضَلَ صَلاَةِ المَرْءِ فِي بَيْتِهِ إِلَّا الصَّلاَةَ المَكْتُوبةَ».
[صحيح] - [متفق عليه]

Zayd ibn Thābit (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) took for himself a room in the mosque made of straw mats. He prayed in it for a few nights until some people gathered with him for the night prayer. One night they did not hear his voice and thought he had slept, so some of them started to attract his attention to their presence by clearing their throats so that he would come out. The Prophet (may Allah's peace and blessings be upon him) then said: "You kept doing what I saw you doing till I feared that this prayer might become obligatory upon you, and if it were to become obligatory upon you, you would not be able to observe it. O people, pray at your homes, for a person’s best prayer is the one he offers at his home except the obligatory prayer."
Sahih/Authentic. - [Al-Bukhari and Muslim]

Explanation

This Hadīth informs us that the Prophet (may Allah's peace and blessings be upon him) took for himself a room made of straw mats in a corner of the mosque. Apparently, he was observing I‘tikāf and was performing Qiyām in that room. When some Muslims heard him pray, they stood in rows behind him in congregation. They kept doing this for some nights until one night they did not hear his voice. They thought he was asleep so they started to make some sounds so as to wake him up. The Prophet (may Allah's peace and blessings be upon him) came out to them and told them that he was not asleep, but that he feared that if they kept doing this, the voluntary night prayer would become obligatory upon them. He further explained that if it became obligatory to perform the night prayer, they would not be able to observe it. He also informed them that the best voluntary prayer is that offered in one’s house.