Abdur Rahman bin Mahdi عبد الرحمن بن مهدي · The Book of Oaths and Vows

"We were talking about something, and I had only recently left Jahiliyyah behind, so I swore by Al-Lat and Al-'Uzza. The Companions of the Messenger of Allah said to me: 'What a bad thing you have said! Go to the Messenger of Allah and tell him, for we think that you have committed Kufr.' So I went to him and told him, and he said to me: 'Say: La ilaha illallah wahdahu la sharika lah (There is none worthy of…