Keeping promises and Fulfilling pledges [loyalty]: Imam Ali (as)

Indeed promises are [like] collars around the necks [of people] until the Day of Resurrection, so whoever fulfils them is delivered by Allah, and whoeve breaks them is forsaken by Allah, and whoever takes them lightly, they will take their plea to the One who has enjoyed them and has ordered His creation to fulfil them.

Do not renege on your covenant and do not break your pledge; and do not double-cross your enemy, for Allah has made his covenant and his pact a safety for him.

One of the most honourable of traits is safeguarding [and fulfilling] your pledges.

One of the most honourable of traits is being faithful to your pledges.

He who does not observe his promises and agreements has no conviction in Allah.

One who enters upon the springs of loyalty is quenched by the drink of purity.

People are safe from the betrayal of one in whose heart resides loyalty.

One of the signs of faith is fulfilling promises.

Keeping promises is from the perfection of [one's] magnanimity.

From the best [teachings] of Islam is the fulfilling of pledges.

How good is loyalty and how evil is treachery!

He who delays in fulfilling a promise has not kept it.

Fulfilling [one's] pledges is the adornment of honour.

One who breaks his pledge earns dispraise.

For every pledge that is broken there is uncertainty.