بُلُوغُ الْمَرَامِ
Bulugh al-Maram 408
The Book of Prayer
وَعَنْ زَيْدِ بْنِ ثَابِتٍ - رضى الله عنه - قَالَ: { اِحْتَجَرَ رَسُولُ اَللَّهِ - صلى الله عليه وسلم -حُجْرَةً بِخَصَفَةٍ, فَصَلَّى فِيهَا, فَتَتَبَّعَ إِلَيْهِ رِجَالٌ, وَجَاءُوا يُصَلُّونَ بِصَلَاتِهِ... } اَلْحَدِيثَ, وَفِيهِ: { أَفْضَلُ صَلَاةِ اَلْمَرْءِ فِي بَيْتِهِ إِلَّا اَلْمَكْتُوبَةَ } مُتَّفَقٌ عَلَيْه ِ [1] .
Narrated Zaid bin Thabit (RA): Allah's (ﷺ) made a small room of a mat (i.e. he used it to designate a space for prayer) and prayed inside it. The people followed him, and they came to pray behind him. The narrator mentioned the rest of the Hadith, and it contains the words: "The most excellent prayer of a person is (that which he prays) in his house except that which is prescribed (the five congregational prayers)." [Agreed upon].
Sunnah.com reference: Book 2, Hadith 313