Once an oath is taken, once a pledge is made, once a covenant is established, it should be held as a sacred undertaking, and may not be broken, as is ordained:
‘’Fulfil God’s covenant, when you make a covenant, and do not break your oaths after ratifying them. You have made God your guarantor, and God knows what you do’’ (16:91)
Whether it refers to an individual, a community or a nation, an oath, a pledge, a covenant needs to be respected as it is affirmed in honest faith with God the guarantor of whatever you might have undertaken to do, to fulfil. Oaths may not be taken as means of deception, as enshrined in the Ayah following the one noted above:
‘’And do not be like her who unravels her yarn, breaking it into pieces after she spun it strongly. Nor use you oaths as a means of deception among you, because one community is more prosperous than the other. God is testing you thereby. On the day of Resurrection, He will make clear to you everything, you have disputed about’’ (16:92)
Oaths, pledges, covenant may be taken analogous to the yarn that has been spun with effort, in order to lend strength to it. And breaking an oath would amount to unravelling the yarn spun in a manner of lending it strength. It would mean wasting an effort, wasting an investment in a sacred deed.
Pledges made to others on an individual level, a societal level, or where it involves a deal between nations must be upheld. And, it may not be taken as a ruse, or used as a mean of deception, because one community or a nation is more prosperous than the other in the equation.
The oath, the pledge, the covenant may be taken as a test from the God—test of affirmation of the oath taken, a pledge made or a covenant established.