Ma'qil bin Yasar (may Allah be pleased with him) said: I had a sister. People sent me proposals of marriage for her, but I refused them. Eventually my paternal cousin came and expressed his wish to marry her, and I married her to him. They lived together for as long as Allah willed; then he divorced her. He had the right to take her back, but he did not take her back, and so her waiting period passed. When other people's proposals began to come to me, he too came again with a proposal, along with the other suitors. I said: "I refused the people and preferred you for her. Then you divorced her although you could have taken her back; then you left her until her waiting period passed, and now, when proposals are coming from others, you have come along with the suitors. I will never marry her to you." Then Allah revealed this verse: "And when you divorce women and they reach the end of their waiting period, do not prevent them from marrying their husbands" [Surah al-Baqarah: 232]. Then I made expiation for my oath and married her to him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13596