Whoever deliberately breaks their fast during the day in Ramadan commits a major sin and will face severe warnings for their action, as the Prophet Muhammad (peace be upon him) informed: "While I was sleeping, two men came to me and took me by my arms, bringing me to a steep mountain. They said to me: 'Climb.' When I reached the middle of the mountain, I heard a loud voice. I asked: 'What is this sound?' They said: 'This is the howling of the people of Hell.' Then they took me away, and I saw people hanging by their heels, their mouths split open, and blood flowing from their mouths. I asked: 'Who are these?' They said: 'These are those who break their fast before the time of breaking their fast.'" This is in Sahih Ibn Hibban 16: 536, Al-Mustadrak 1: 595, and Sunan Al-Nasa'i 2: 246. This applies to those who hasten to break their fast before sunset, so what about those who do not fast at all? They are required to make up the fast and perform a compensatory act, which is in order: freeing a slave, and if unable, then fasting two consecutive months, and if unable, then feeding sixty needy people. They must also repent to Allah and observe the rest of the day in a manner resembling those who are fasting. See: Al-Mabsut 1: 116, 3: 71, and Bada'i' Al-Sana'i 2: 103. It was narrated from Salama bin Al-Akwa' (may Allah be pleased with him) that the Prophet (peace be upon him) commanded a man from Aslam to announce to the people that whoever has eaten should fast the rest of their day, and whoever has not eaten should fast, for today is the Day of Ashura." This is in Sahih Al-Bukhari 2: 705, Sahih Ibn Hibban 8: 385, and Al-Mustadrak 3: 608. Ashura was an obligatory fast before the obligation of Ramadan. And because the time of Ramadan is a noble time, it is necessary to honor this time as much as possible. If one is unable to honor it by fasting, they should honor it by resembling those who are fasting; fulfilling their right as much as possible if they are capable of resembling them, and avoiding putting themselves in suspicion. See: Bada'i' Al-Sana'i 2: 103.