Sunan an-Nasa'i, Volume 3, Book 24, Hadith 2737 (DarusSalam) ⓘ
It was narrated that Ibn 'Abbas said: "I heard 'Umar say" 'By Allah, I forbid you to forbid you to perform Tamattur,' but it is mentioned in the Book of Allah and the Messenger of Allah did it" meaning 'Umrah with Hajj.
أَخْبَرَنَا مُحَمَّدُ بْنُ عَلِيِّ بْنِ الْحَسَنِ بْنِ شَقِيقٍ، قَالَ أَنْبَأَنَا أَبِي قَالَ، أَنْبَأَنَا أَبُو حَمْزَةَ، عَنْ مُطَرِّفٍ، عَنْ سَلَمَةَ بْنِ كُهَيْلٍ، عَنْ طَاوُسٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ سَمِعْتُ عُمَرَ، يَقُولُ وَاللَّهِ إِنِّي لأَنْهَاكُمْ عَنِ الْمُتْعَةِ، وَإِنَّهَا، لَفِي كِتَابِ اللَّهِ وَلَقَدْ فَعَلَهَا رَسُولُ اللَّهِ صلى الله عليه وسلم يَعْنِي الْعُمْرَةَ فِي الْحَجِّ .
also referenced under: Hadith 2736 (Reference) & Book 24, Hadith 0 (In-Book)