In the first verse of Surah al-Ma'idah, Allah called upon the believers: "O you who believe! Fulfill your promises." [5:1] In Surah Maryam, Allah also praised Prophet Ismail: "He was true to his promise, He was a Messenger and a Prophet." [19:54]
Keeping appointments is vital to our lives. Time is the most precious commodity; once wasted, it can never be recovered. If you made an appointment, whether with a friend, colleague or for business, you should do your utmost to keep this appointment.
This is the right of the other persons who, despite other commitments, favored you with a part of their valuable time. If you do not come on time, not only have you disrupted their schedule but you have also marred your image and reputation. If your punctuality becomes poor you will lose people's respect. You should keep all your appointments whether they are with an important person, a close friend or a business colleague.You will then be responding to the call of Allah in Surah al-Isra: "And keep the promise; the promise is a responsibility." [17:34]
It is enough to know that our kind Prophet, sallallahu `alayhi wa sallam, gave an appointment to one of his companions. The companion came three days later. The Prophet, sallallahu `alayhi wa sallam, gently reprimanded him saying: "You have caused me some trouble. I have been waiting for you for three days."The companion probably had an excuse for this delay; however, he had no means by which to inform the Prophet, sallallahu `alayhi wa sallam, about his inability to keep the appointment.
Today, fast and reliable communication means are available everywhere. Therefore, as soon as you realize you will be unable to keep an appointment, you should inform the other parties to enable them to utilize their time elsewhere. Do not be careless or irresponsible assuming that since the appointment is relatively unimportant, it does not merit a notice or an apology.This is totally irrelevant. Regardless of its importance, an appointment is a commitment that should be kept or properly cancelled in advance.
Never make a promise while intending not to keep it. This is forbidden as it falls within lying and hypocrisy. Al-Bukhari and Muslim narrated that the Prophet said: "Three traits single out a hypocrite, even if he prays or fasts and claims to be Muslim: If he speaks, he lies. If he makes a promise, he does not keep it. If he is entrusted, he betrays the trust." [Al-Bukhari and Muslim]
Imam Al-Ghazali in al-Ihya explains that this hadith is applicable to those who promise while intending not to fulfill it, or those who, without an excuse, decide later not to fulfill the promise. Those who promise but could not fulfill their promise due to a proper excuse are not hypocrites. But we should be careful not to present a false excuse, as Allah knows our inner thoughts and intentions.