Hadith Q2990
وَإِنْ لَمْ يَكُنْ ذَلِكَ وَاجِبًا إِذِ الْخُلَفَاءُ الرَّاشِدُونَ الْمَهْدِيُّونَ الَّذِينَ أَمَرَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بِالْعَضِّ بِالنَّوَاجِذِ عَلَى سُنَّتِهِ وَسُنَّتِهِمْ قَدِ اقْتَدَوْا بِالنَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بِالنُّزُولِ بِهِ.
Although this act is not obligatory, it is recommended because the rightly guided caliphs stayed in this valley following the example of the Noble Prophet (peace be upon him), and the Noble Prophet (peace be upon him) has commanded to hold firmly to his Sunnah as well as the Sunnah of the rightly guided caliphs.
Hadith 2990
Sayyiduna Ibn Umar (may Allah be pleased with them both) narrates that the Messenger of Allah (peace be upon him), Sayyiduna Abu Bakr, Umar, and Uthman (may Allah be pleased with them all), all of them used to stay in the valley of Abtah.
Hadith 2991
A narration similar to the aforementioned is reported from Sayyiduna Ibn Umar (may Allah be pleased with them both).