Marwan bin Salim al-Muqaffa' said: I saw Ibn Umar (may Allah be pleased with them both), then he narrated the hadith, that when the Messenger of Allah (peace and blessings be upon him) broke his fast he would say: 'Dhahaba al-zama'u wabtallati al-'uruqu wa thabata al-ajru in sha' Allah' ("The thirst has gone, the veins are moistened, and the reward is confirmed, if Allah wills.")
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8133