Yahya related to me from Malik from Nafi that Abdullah ibn Umar used to do kaffara for a broken oath by feeding ten poor people. Each person got a mudd of wheat. He sometimes freed a slave if he had repeated the oath.
أَنَّهُ كَانَ يُكَفِّرُ عَنْ يَمِينِهِ بِإِطْعَامِ عَشَرَةِ مَسَاكِينَ لِكُلِّ مِسْكِينٍ مُدٌّ مِنْ حِنْطَةٍ وَكَانَ يَعْتِقُ الْمِرَارَ إِذَا وَكَّدَ الْيَمِينَ