Sahih Muslim , Book 15, Hadith 365 (In-Book) ⓘ

Adullah b. 'Amr (b. al-'As) (Allah be pleased with him) reported that a person came to Allah's Apostle and said: I got (my head) shaved before sacrificing the, animal, whereupon be (the Holy Prophet) said: Sacrifice the animal (now) ; there is no harm in it. He (the person said): I sacripced the animal before throwingpebbles. whereupon he said: Throw pebbles (now) ; there is no harm in it.

وَحَدَّثَنَاهُ أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَزُهَيْرُ بْنُ حَرْبٍ، قَالَ أَبُو بَكْرٍ حَدَّثَنَا ابْنُ عُيَيْنَةَ، عَنِ الزُّهْرِيِّ، عَنْ عِيسَى بْنِ طَلْحَةَ، عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو، قَالَ أَتَى النَّبِيَّ صلى الله عليه وسلم رَجُلٌ فَقَالَ حَلَقْتُ قَبْلَ أَنْ أَذْبَحَ ‏.‏ قَالَ ‏"‏ فَاذْبَحْ وَلاَ حَرَجَ ‏"‏ ‏.‏ قَالَ ذَبَحْتُ قَبْلَ أَنْ أَرْمِيَ ‏.‏ قَالَ ‏"‏ ارْمِ وَلاَ حَرَجَ ‏"‏ ‏.‏