Hazrat Usman Bati narrates that Hazrat Anas bin Sirin fasted on the Day of Arafah, but he became extremely thirsty and broke his fast. After that, he asked many companions of the Prophet about this matter, and all of them instructed him to make up for it by fasting one day in compensation.

Hazrat Ibn Abbas (may Allah be pleased with both of them) says that for breaking a voluntary fast, one should make up for it by fasting one day.

Hazrat Abdur Rahman bin Yazid bin Jabir narrates that I asked Hazrat Mak’hool about a person who keeps a fast and then breaks it. He replied that he will make up for one day.

Hasan says that if a person has eaten suhoor, then fasting becomes obligatory upon him; if he breaks the fast, then making it up (qada) is necessary for him.

Hazrat Abdullah bin Muslim narrates that if Hazrat Ata and Hazrat Mujahid went to meet someone and they were fasting, and in that state they were invited to eat, they would break their fast and say that they would make up for it by fasting another day.

Hazrat Umm Hani states that I was sitting with the Noble Prophet (peace and blessings be upon him). Something to drink was brought to him, which he drank. He gave it to me, and I also drank from it. Then I said, "O Messenger of Allah! I have committed a sin, please seek forgiveness for me." He asked, "What sin have you committed?" I said, "I was fasting and I broke my fast." He said, "Were you making up a missed fast?" I replied, "No." The Prophet (peace and blessings be upon him) said, "There is no harm for you in this."

Hazrat Ikrimah states that Ibn Abbas (may Allah be pleased with them) used to break a voluntary fast and did not mind it.

Hazrat Yusuf bin Mahak Makki says that Hazrat Abdullah bin Abbas (may Allah be pleased with them) had intercourse with one of his slave women while he was fasting. Someone said to him, "You have had intercourse with her while fasting?" He replied, "She was my slave woman, I liked her. Besides, the fast was voluntary (nafl)."

Hazrat Sha'bi did not consider it objectionable for a person to break a voluntary fast.

Hazrat Aisha (may Allah be pleased with her) narrates that sometimes a fine and rare thing would be gifted to us. We would say to the Messenger of Allah (peace and blessings be upon him) that if you were not fasting, we would have presented this to you. He would have that thing brought and we would break our fast with it.