بُلُوغُ الْمَرَامِ
Bulugh al-Maram 264
The Book of Prayer
وَعَنْ اِبْنِ عَبَّاسٍ -رَضِيَ اَللَّهُ عَنْهُمَا- قَالَ: قَالَ رَسُولُ اَللَّهِ - صلى الله عليه وسلم -{ مَا أُمِرْتُ بِتَشْيِيدِ اَلْمَسَاجِدِ } أَخْرَجَهُ أَبُو دَاوُدَ , وَصَحَّحَهُ اِبْنُ حِبَّانَ . [1]
Narrated Ibn 'Abbas (RA): Allah's Messenger (ﷺ) said: "I was not commanded to build beautified mosques". [Reported by Abu Dawud and Ibn Hibban graded it Sahih (authentic)]
Sunnah.com reference: Book 2, Hadith 136