Sahih al-Bukhari 23:95
Narrated Ibn `Abbas:
The Prophet (p.b.u.h) offered the funeral prayer of a man one night after he was buried, he and his companions stood up (for the Prayer). He had asked them about him before standing, saying, "Who is this?" They said, "He is so and so and was buried last night." So all of them offered the funeral prayer.
Reference
Sahih al-Bukhari 23:95
In-book reference
Book 23, Hadith 95
Arabic Text
حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا جَرِيرٌ، عَنِ الشَّيْبَانِيِّ، عَنِ الشَّعْبِيِّ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ صَلَّى النَّبِيُّ صلى الله عليه وسلم عَلَى رَجُلٍ بَعْدَ مَا دُفِنَ بِلَيْلَةٍ قَامَ هُوَ وَأَصْحَابُهُ، وَكَانَ سَأَلَ عَنْهُ فَقَالَ " مَنْ هَذَا ". فَقَالُوا فُلاَنٌ، دُفِنَ الْبَارِحَةَ. فَصَلَّوْا عَلَيْهِ.