Is it permissible to break a promise without an excuse?

Question : The scholars (may Allah have mercy on them) differed on whether, if you promise someone a specific time, it is permissible to break that promise without a dire necessity or not. For example, if you say, "I will come to you tomorrow for an invitation to a du'a, either lunch or dinner or something similar," is it permissible to break the appointment?

Answer : Some scholars say that if you break an appointment, you are not affected. However, the correct view is that you commit a sin unless there is a Shari'ah excuse. If you promise your brother a specific time, you must fulfill it because you promised him, and breaking a promise is one of the signs of hypocrisy. Would you be content to be a hypocrite? No one is content with that. The correct position, indicated by the Sunnah, is that fulfilling the promise is obligatory, and this is the choice of Shaykh al-Islam Ibn Taymiyyah (may Allah have mercy on him), because breaking it is hypocrisy. However, if you have an excuse, or if you did not give a clear appointment by saying to your companion, "I will come to you if Allah wills, if I have no excuse," then if you have an excuse, there is no harm; you are in a state of leniency because you did not give him a clear appointment. Likewise, if you break the promise for an excuse, such as if fulfilling the promise requires a cigarette and you went out and the car broke down and you were unable to reach him at the appointed time, then this is undoubtedly an excuse that prevented you.