Harmony is a Quality of the 5th. Ray.

Being harmonious in every situation is the first lesson in self-mastery.
Harmony is a state of peaceful agreement and co-operation.
When you have harmony in your thoughts then your actions will be controlled and harmonious.
When your emotions are in harmony you will produce harmony in your spoken words. Therefore to keep your peace and therefore your harmony, in all your life situations:–stop any senseless chattering / do not engage in talk which degrades yourself or others /practice silence rather than speak harshly or discordantly.
Ultimately , you cannot have inner or outer peace or have a life of harmony if you have debts that you owe life. So , owe no man anything and pay back what you owe.
To deal with spiritual debts that you have made in this lifetime and previous lifetimes, you can use powerful spiritual techniques, such as Violet Flame decrees and rosaries.