What is the ruling on breaking a covenant and treachery in Islam, with evidence from the Qur’an and Sunnah?

Fulfilling a covenant is obligatory, and breaking or betraying it is forbidden. Allah Almighty said: "And fulfill the covenant of Allah when you have covenanted, and do not break the oaths after their confirmation while you have made Allah, over you, a security. Indeed, Allah knows what you do." And He said: "And fulfill [every] covenant. Indeed, the covenant will be questioned about." In the noble Hadeeth, among the characteristics of a hypocrite is: "If he makes a covenant, he betrays it."