Yahya said: If the waiting period expires before he takes her back, then it is a final release (tasrih). "And do not take the verses of Allah in mockery."
Yahya [narrated] from Sulayman ibn Arqam, from al-Hasan, from Abu al-Darda' who said: "A man would divorce; then when asked, he would say: 'I was only joking.' And he would marry; then when asked, he would say: 'I was only joking.' And he would emancipate; then when asked, he would say: 'I was only joking.' So Allah revealed: 'And do not take the verses of Allah in mockery.' And the Messenger of Allah (peace be upon him) said: 'Whoever divorces while joking, or marries while joking, or emancipates while joking, it is legally binding.'"