Good Manners and Form (Al-Adab)
Ṣaḥīḥ al-Bukhārī 6049
خَرَجْتُ لأُخْبِرَكُمْ، فَتَلاَحَى فُلاَنٌ وَفُلاَنٌ وَإِنَّهَا رُفِعَتْ، وَعَسَى أَنْ يَكُونَ خَيْرًا لَكُمْ، فَالْتَمِسُوهَا فِي التَّاسِعَةِ وَالسَّابِعَةِ وَالْخَامِسَةِ
kharajtu lʾukhbirakum, fatalāḥā fulānun wafulānun wa-innahā rufiʿat, waʿasā an yakūna khayran lakum, fa-at-tamisūhā fī at-tāsiʿah wa-as-sābiʿah wa-l-khāmisah
Transliteration generated from the Arabic vowel marks
The full narration
Narrated 'Ubada bin As-Samit:Allah's Messenger (ﷺ) went out to inform the people about the (date of the Night of decree (Al-Qadr). There happened a quarrel between two Muslim men. The Prophet (ﷺ) said, "I came out to inform you about the Night of Al-Qadr, but as so-and-so and so-and-so quarrelled, so the news about it had been taken away; and may be it was better for you. So look for it in the ninth, the seventh, or the fifth (of the last ten days of Ramadan)
Source
Ṣaḥīḥ al-Bukhārī · 6049