Sunan Abi Dawud, Book 24, Hadith 3579 (USC-MSA) ⓘ
Narrated Umar ibn al-Khattab: Umar said while he was (sitting) on the pulpit: O people, the opinion from the Messenger of Allah was right, because Allah showed (i.e. inspired) him; but from us it is sheer conjecture and artifice.
حَدَّثَنَا سُلَيْمَانُ بْنُ دَاوُدَ الْمَهْرِيُّ، أَخْبَرَنَا ابْنُ وَهْبٍ، عَنْ يُونُسَ بْنِ يَزِيدَ، عَنِ ابْنِ شِهَابٍ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ، - رضى الله عنه - قَالَ وَهُوَ عَلَى الْمِنْبَرِ يَا أَيُّهَا النَّاسُ إِنَّ الرَّأْىَ إِنَّمَا كَانَ مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم مُصِيبًا لأَنَّ اللَّهَ كَانَ يُرِيهِ وَإِنَّمَا هُوَ مِنَّا الظَّنُّ وَالتَّكَلُّفُ .
also referenced under: Hadith 3586 (DarusSalam) & Hadith 3579 (Hasan)