Surah An-Nahl (16) — Ayah 92

92. And do not be like the woman who untwisted her yarn after spinning it strongly [95], breaking it into pieces. You use your oaths as a means of deception among yourselves so that one group may take advantage over another. Allah only tests you through these (oaths and agreements) [96]. And on the Day of Resurrection, He will surely make clear to you that about which you used to differ.

[95]
Prohibition of Breaking Agreements:

In Makkah, there lived a mentally unstable woman whose name became Khirqā’ (the one who breaks apart). She would spin thread all day and then break it apart and throw it away. [بخاري۔ كتاب التفسير۔ تفسير سورة نحل]
Allah Almighty, giving the example of this woman, said that you should not consider your mutual agreements like weak thread, breaking your agreement whenever you wish, and do not become mad like that woman. The disbelieving tribes of Arabia were such that they would make a pact of friendship with one tribe and swear oaths, then, upon finding another tribe stronger than the first, they would break the first pact and make a pact with the stronger tribe. Some tribes even did the same with the Muslims: first, they made a pact of friendship with them, but when they saw the Quraysh of Makkah gaining the upper hand, they broke their pact with the Muslims and befriended the Quraysh. Muslims were strictly forbidden from such self-serving behavior. And today, the situation is such that modern politics is based entirely on self-interest; the same actions that the disbelieving tribes of that era used to do are now being done by so-called civilized governments, and in this respect, they have even surpassed those disbelieving tribes: their public agreements and oaths are of one kind, while their secret agreements are completely different and even contrary to their public agreements. In other words, in the successful politics of the present age, not only is breaking agreements included, but also the element of hypocrisy. Such cunning is now called "diplomacy" in today’s language, and instead of considering such breaking of agreements and hypocrisy as shameful, it is considered successful politics, and nations encourage such dishonest leaders and consider them successful leaders. And this is especially what is happening with Muslim countries nowadays: outwardly, they increase ties of friendship, while secretly, they leave no stone unturned in undermining them. And Muslim countries, due to lack of trust in Allah and their own incompetence, have been repeatedly deceived by these civilized nations for ages. Yet, they are not granted the ability to set aside their differences, unite, and stand firm before these disbelieving governments.

Democracy and "Lotaism":

This is the state of current governments. The state of individuals is not much different. Nowadays, it is the era of democracy and assemblies. Elected members of assemblies, for the sake of their own interests, immediately break their loyalty to their previous political party and join the ruling party. In today’s political terminology, they are called "Lotay" (turncoats), which means such unprincipled and irreligious people are like bottomless vessels that roll wherever they see their own interest or receive some cash. They have no regard for their agreements.

[96]
One Should Fulfill Agreements Without Regard for Worldly or Religious Interests:

This is a test to see whether you remain committed to your agreements regardless of your interests, whether worldly or religious. In no case is it permissible for a Muslim to break an agreement. The interests of Islam and Muslims cannot be an obstacle to honoring agreements. The best example of honoring an agreement is the incident that occurred on the battlefield of Badr. Two Muslims, Hudhayfah bin Yaman and Abu Husayl, came to the Prophet ﷺ to join the battle and also informed him that they had fallen into the hands of the disbelievers and were released on the condition that they would not participate in the battle. Accordingly, the Prophet ﷺ sent both of them back, saying that since you have made an agreement with them, you must fulfill your agreement. [مسلم۔ کتاب الجہادو السیر۔ باب الوفا بالعہد]
Even though at that time the Prophet ﷺ was in dire need of manpower. And those who, in the name of religious interests, would break agreements and consume others’ wealth by any lawful or unlawful means were the Jews, who had made it their principle that: ﴿لَيْسَ عَلَيْنَا فِي الْاُمِّيّٖنَ سَبِيْلٌ﴾ (i.e., whatever we do to a non-Jew, we will not be held accountable for it).