Mishkat al-Masabih 1182

Ka‘b b. ‘Ujra said that the Prophet (ﷺ) came to the mosque of the B. ‘Abd al-Ashhal and prayed the sunset prayer in it. When the people finished their prayer he saw them performing tasbih after it and said, “This is the prayer to be observed at home.”* * This refers to supererogatory prayers. Tasbih is the utterance of 'Glory be to God!’ Abu Dawud transmitted it. In the version by Tirmidhi and Nasa’i it says that the people got up and offered supererogatory prayers, whereupon the Prophet (ﷺ) said, “Observe this prayer at home.”