Sahih Bukhari Volume 1, Book 3, Hadith 83

حَدَّثَنَا إِسْمَاعِيلُ، قَالَ حَدَّثَنِي مَالِكٌ، عَنِ ابْنِ شِهَابٍ، عَنْ عِيسَى بْنِ طَلْحَةَ بْنِ عُبَيْدِ اللَّهِ، عَنْ عَبْدِ اللَّهِ بْنِ عَمْرِو بْنِ الْعَاصِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم وَقَفَ فِي حَجَّةِ الْوَدَاعِ بِمِنًى لِلنَّاسِ يَسْأَلُونَهُ، فَجَاءَهُ رَجُلٌ فَقَالَ لَمْ أَشْعُرْ فَحَلَقْتُ قَبْلَ أَنْ أَذْبَحَ‏.‏ فَقَالَ ‏"‏ اذْبَحْ وَلاَ حَرَجَ ‏"‏‏.‏ فَجَاءَ آخَرُ فَقَالَ لَمْ أَشْعُرْ، فَنَحَرْتُ قَبْلَ أَنْ أَرْمِيَ‏.‏ قَالَ ‏"‏ ارْمِ وَلاَ حَرَجَ ‏"‏‏.‏ فَمَا سُئِلَ النَّبِيُّ صلى الله عليه وسلم عَنْ شَىْءٍ قُدِّمَ وَلاَ أُخِّرَ إِلاَّ قَالَ افْعَلْ وَلاَ حَرَجَ

Narrated By 'Abdullah bin Amr bin Al 'Aas : Allah's Apostle stopped (for a while near the Jimar) at Mina during his last Hajj for the people and they were asking him questions. A man came and said, "I forgot and got my head shaved before slaughtering the Hadi (sacrificing animal)." The Prophet said, "There is no harm, go and do the slaughtering now." Then another person came and said, "I forgot and slaughtered (the camel) before Rami (throwing of the pebbles) at the Jamra." The Prophet said, "Do the Rami now and there is no harm."The narrator added: So on that day, when the Prophet was asked about anything (as regards the ceremonies of Hajj) performed before or after its due time, his reply was: "Do it (now) and there is no harm."