Abu al-Bakhtari (may Allah have mercy on him) narrated that Salman (may Allah be pleased with him) acquired a slave girl and said to her in Persian: "Pray." She said: No. He said: "Then make just one prostration." She said: No. It was said: O Abu Abdullah! What benefit will one prostration be to her? He said: "If she prayed, she would pray; and the one who has a share in Islam is not like the one who has no share."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6029