Muwatta Malik 1039

وَحَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، قَالَ الأَضْحَى يَوْمَانِ بَعْدَ يَوْمِ الأَضْحَى ‏.‏ وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ عَنْ عَلِيِّ بْنِ أَبِي طَالِبٍ، مِثْلُ ذَلِكَ ‏

Yahya related to me from Malik from Nafi that Abdullah ibn Umar said, "The sacrifice can be done up to two days after the Day of Sacrifice." Yahya related to me from Malik that he had heard the same from Ali ibn Abi Talib

Reference

Muwatta Malik 1039

In-book

Book 23, Hadith 12