Sunan an-Nasai Book 40, Hadith 4212

أَخْبَرَنَا أَحْمَدُ بْنُ سُلَيْمَانَ، قَالَ حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ حَدَّثَنَا دَاوُدُ بْنُ قَيْسٍ، عَنْ عَمْرِو بْنِ شُعَيْبٍ، عَنْ أَبِيهِ، عَنْ جَدِّهِ، قَالَ سُئِلَ رَسُولُ اللَّهِ صلى الله عليه وسلم عَنِ الْعَقِيقَةِ فَقَالَ ‏"‏ لاَ يُحِبُّ اللَّهُ عَزَّ وَجَلَّ الْعُقُوقَ ‏"‏ ‏.‏ وَكَأَنَّهُ كَرِهَ الاِسْمَ قَالَ لِرَسُولِ اللَّهِ صلى الله عليه وسلم إِنَّمَا نَسْأَلُكَ أَحَدُنَا يُولَدُ لَهُ ‏.‏ قَالَ ‏"‏ مَنْ أَحَبَّ أَنْ يَنْسُكَ عَنْ وَلَدِهِ فَلْيَنْسُكْ عَنْهُ عَنِ الْغُلاَمِ شَاتَانِ مُكَافَأَتَانِ وَعَنِ الْجَارِيَةِ شَاةٌ ‏"‏ ‏.‏ قَالَ دَاوُدُ سَأَلْتُ زَيْدَ بْنَ أَسْلَمَ عَنِ الْمُكَافَأَتَانِ قَالَ الشَّاتَانِ الْمُشَبَّهَتَانِ تُذْبَحَانِ جَمِيعًا ‏.‏

It was narrated from 'Amr bin Shuaib, from his fahther, that his grandfather said:"The messenger of Allah was asked about the 'Aqiqah and he said: "Allah, the mighty and sublime, does not like Al-Uquq' as if he disliked the word (Al-Aqiqah). He said to the Messenger of Allah: 'But one of us may offer a sacrifice when a child is born to him.' He said: 'Whoever wants to offer a sacrifice for his child, let him do so, for a boy; two sheep, Mukafaatan, (of equal age), and for a girl, one.' (One of the narrators) Dawud said: 'I asked Ziad bin Aslam about the word Mukafaatan and he said: 'Two similar sheep that are slaughtered together