St. Gregory of Nyssa, St. Gregory the Theologian, Lorenzo Scupoli, St. Gregory Palamas and Plato.
According to our wise teacher (St. Gregory of Nyssa) the soul is tripartite.
When virtue is in the mental part it is called circumspection, sagacity and wisdom.
When it is in the desiring part it is called chastity, love and self-mastery.
When it is in the excitable part it is called courage and patience.
~ Abba Evagrius the Monk(Texts on Active Life no. 61)
Every deiform soul is tripartite, according to Gregory the Theologian.
Virtue, when established in the intelligence, he calls discretion, understanding and wisdom;
and when in the incensive power, he calls it courage and patience;
and when in the faculty of desire, he calls it love, self-restraint and self-control.
~ St. Theodoros the Great Ascetic (A Century of Spiritual Texts no. 24)
Our soul has three parts or powers - the thinking, the desiring and the excitable.
Owing to their corruption, these three powers give birth to three corresponding kinds of wrong thoughts and movements.
The thinking power gives birth to thoughts of ingratitude to God and complaints, forgetfulness of God, ignorance of divine things, ill-judgment and all kinds of blasphemous thoughts.
The desiring power gives birth to pleasure-loving thoughts, thoughts of vain-glory, love of money and all their numerous ramifications, belonging to the domain of self-indulgence.
The excitable power gives birth to thoughts of anger, hatred, envy, revenge, gloating, ill-will, and generally to all evil thoughts.
~ Lorenzo Scupoli (Unseen Warfare:Chapter 1
The soul is tripartite and is considered as having three powers: the intelligent, the incensive, and the appetitive.
Because the soul was ill in all three powers, Christ, the soul's Healer, began His cure with the last, the appetitive.
For desire unsatisfied fuels the incensive power, and when both the appetitive and incensive powers are sick they produce distraction of mind.
Thus the soul's incensive power will never be healthy before the appetitive power is healed;
nor will the intelligence be healthy until the other two powers are first restored to health.
~ St. Gregory Palamas (To the Most Reverend Nun Xenia no. 29)
Human behaviour flows from three main sources: desire, emotion, and knowledge.
~ Plato
thanks to:
https://www.orthodox.net/gleanings/soul.html