Continuous Fasting
Question :
What is continuous fasting and is it Sunnah?
Answer:
Continuous fasting is that a person does not break his fast for two days. Thus, he continues fasting for two consecutive days. Indeed the Prophet prohibited this and he said:
"Whoever wants to continue fasting (ie., after sunset), then let him continue (only) until late night just before dawn."
Therefore, continuing fasting until late night before dawn is considered permissible and it is not considered legislated. The Messenger encouraged hastening the breaking of the fast. He said:
"The people will not cease being upon good as long as they hasten the breaking of the fast."
However, he allowed them to continue fasting until late night before dawn only. When they said: "O Messenger of Allâh, verily you practice continuous fasting," he said:
"Verily, I am not like you all."
Source:
Ash-Shaykh Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 3 Pages 329-330