Abū Hurairah (may Allah be pleased with him) states: “My mother was a polytheist, and I used to invite her to embrace Islam. One day when I presented Islamic Dawah to my mother, she uttered some words against the Prophet, which were unpleasant to me. I went to the Prophet, crying, and said: ‘O Messenger of Allah! I invite my mother to accept Islam, but she refuses. Today when I presented Islamic Dawah to her, she said something about you which I did not want to hear. You pray to Allah that He may give guidance to Abū Hurairah’s mother.’ The Prophet prayed and said: ‘O God! Give guidance to the mother of Abū Hurairah.’
Gladdened by this prayer of the Prophet, I started for home. On reaching there, I found that the door of the house was closed. My mother, hearing my steps, called: ‘Abū Hurairah! Wait!’ I heard the sound of water dropping. She had bathed and put on kurta, and did not take odhni (covering cloth) in haste. She opened the door and said: ‘I give witness that there is no God except Allah, and I give witness that Muhammad is His slave and messenger.’
Hearing this, I went to the Prophet in such a condition that tears of happiness were flowing from my eyes, and I said: ‘O Messenger of Allah! Be glad, Allah has accepted your prayer and He has guided the mother of Abū Hurairah.’ Hearing this, the Prophet thanked God, praised Him and said a few auspicious words of kindness.”
(Sahih Muslim)