Abd al-Wahhab bin Ata (may Allah have mercy on him) said that Sa'id bin Abi Arubah (may Allah have mercy on him) was asked about a person who owed two Ramadans and had not been well in between them. He narrated to us from Abu Yazid al-Madani (may Allah have mercy on him) that a man died owing two Ramadans, and he left instructions that the jurists be asked what their expiation is, and (he said:) Pay off my debt for me as well, and begin with the debt of Allah. He narrated the hadith, and in it is: They came to Ibn Abbas (may Allah be pleased with them both) and he said: He owes the feeding of sixty poor people. Then they went back from there to Ibn Umar (may Allah be pleased with them both) and he said: Ibn Abbas (may Allah be pleased with them both) has spoken the truth, so do just that.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8233