Sayyiduna Anas bin Malik (may Allah be pleased with him) says that Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) said concerning a man who gave his wife three divorces before consummating the marriage: All three have taken effect; this woman is not lawful for that man until she marries another man. And when such a person was brought to him, he would punish him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الخلع والطلاق / 14958