What is the proper description of the intention (niyyah) for fasting? Is it valid to make the intention for the entire month, or must it be made for each day separately? Is it permissible to stipulate in the intention: "And if an impediment prevents me, then my dissolution [from ihram] is where I am impeded"?

The intention's place is the heart, and it is not a condition to utter it aloud. Rather, the Muslim's firm resolve to fast at any part of the night is sufficient. It is not permissible to make conditions in fasting because it is not waived for the accountable person who has no excuse. If an excuse arises, Allah has permitted breaking the fast for the sick and the traveler, and has forbidden it for the menstruating woman and the woman in postpartum bleeding.