Allah, Most High, says, {And fulfill (every) engagement, for (every) engagement will be enquired into on the day of reckoning} (AI-Isra: 34)

{O ye who believe! Fulfill (all) obligations?} (AI-Ma'idah: 1)

Az-Zajjaj said engagements include all what Allah commands or forbids. AI-Wahidi also said obligations include what Allah made lawful or unlawful in the Qur'an. Muqatil Ibn Hayyan added, it is also included the convenants held among Muslims or between Muslim and non- Muslims.

The Prophet (pbuh) said, "There are four (habits) which, if found in a person, he is a perfect hypocrite. If one of these is found in a person, then he has one sign of hypocrisy, until he leaves it. These four characteristics of a hypocrite are:

when he is entrusted (with something) he embezzles, when he talks he lies, when he promises he breaks it, and when he argues he starts abusing people.” 1

The Prophet (pbuh) said, "For everyone who breaks his promise, there will be a flag (to mark him out) on the Day of Judgment, and it will be announced that this flag is the symbol of promise by so and so.”2

The Prophet (pbuh) said, "There will be three people against whom I shall fight on the Day of htdgment: one, the person who makes a promise with an oath in my name and then breaks it, two, the person who sells a free man as a slave and appropriates his sale proceed and three, the person who employs, a workman and having taken full work from him fails to pay him his dues.” 3

The Prophet (pbuh) said, "Whoever withdraws himself from an engagement of loyalty will meet Allah with no excuse on the Day of Judgment. The death of someone who dies without the leader of a group over him is as if he had died in the pre-Islamic period of ignorance.” 4