ahya related to me from Malik that he asked Ibn Shihab about the dhihar of a slave. He said, "It is like the dhihar of a free man."
Malik said, "He meant that the same conditions were applied in both cases."
Malik said, "The dhihar of the slave is incumbent on him, and the fasting of the slave in the dhihar is two months. "
Malik said that there was no ila for a slave who pronounced a dhihar from his wife. That was because if he were to fast the kaffara for pronouncing a dhihar, the divorce of the ila would come to him before he had finished the fast.

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، أَنَّهُ سَأَلَ ابْنَ شِهَابٍ عَنْ ظِهَارِ الْعَبْدِ، فَقَالَ نَحْوُ ظِهَارِ الْحُرِّ . قَالَ مَالِكٌ يُرِيدُ أَنَّهُ يَقَعُ عَلَيْهِ كَمَا يَقَعُ عَلَى الْحُرِّ . قَالَ مَالِكٌ وَظِهَارُ الْعَبْدِ عَلَيْهِ وَاجِبٌ وَصِيَامُ الْعَبْدِ فِي الظِّهَارِ شَهْرَانِ . قَالَ مَالِكٌ فِي الْعَبْدِ يَتَظَاهَرُ مِنِ امْرَأَتِهِ إِنَّهُ لاَ يَدْخُلُ عَلَيْهِ إِيلاَءٌ وَذَلِكَ أَنَّهُ لَوْ ذَهَبَ يَصُومُ صِيَامَ كَفَّارَةِ الْمُتَظَاهِرِ دَخَلَ عَلَيْهِ طَلاَقُ الإِيلاَءِ قَبْلَ أَنْ يَفْرُغَ مِنْ صِيَامِهِ .