1601 - Al-Hasan ibn 'Ali al-Khallal narrated to us, saying: Yazid ibn Harun narrated to us, saying: Sa'id ibn Abi 'Arubah informed us, from Qatadah, from al-Hasan, from Samurah ibn Jundub, from the Prophet, peace and blessings be upon him, similar to it(1).

This is a good and authentic hadith.

The practice according to the people of knowledge is this: they recommend that the 'aqiqah be slaughtered for the boy on the seventh day. If it cannot be done on the seventh day, then on the fourteenth day. If it cannot be done then, the 'aqiqah is performed for him on the twenty-first day. They said: nothing is acceptable in the 'aqiqah from the sheep except what is acceptable in the udhiyah (sacrificial animal).

21 - Chapter

1602 - Ahmad ibn al-Hakam al-Basri narrated to us, saying: Muhammad ibn Ja'far narrated to us, from Shu'bah, from Malik ibn Anas, from 'Amr - or 'Umar - ibn Muslim, from Sa'id ibn al-Musayyab, from Umm Salamah, from the Prophet, peace and blessings be upon him, who said: "Whoever sees the crescent of Dhu al-Hijjah and intends to offer a sacrifice, let him not take from his hair nor from his nails"(2).

This is a good hadith(3).

--------------------------------------------
(1) An authentic hadith, like the one preceding it; see its citation there.
(2) An authentic hadith. Muslim (1977), Abu Dawud (2791), Ibn Majah (3149) and (3150), and al-Nasa'i 7/211-212 and 212 also recorded it. It is in the Musnad of Ahmad (26474) and Sahih Ibn Hibban (5897) and (5916).
(3) In the printed edition it appears as "good and authentic" with the additional word "authentic," and it is indeed so.