Ma'qil bin Muqarrin (may Allah be pleased with him) came to Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) and said: My slave has stolen a cloak from my (other) slave. He said: Your property has stolen your property. And he mentioned his slave-girl, that she had committed zina. He said: Flog her. He said: She is not muhsan (married). He said: Her Islam is her ihsan.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 17093