"He is our peace, for he has made both one." Since we think of Christ as our peace, we may call ourselves true Christians only if our lives express Christ by our own peace. As the Apostle says: "He has put enmity to death." We must never allow it to be rekindled in us in any way but must declare that it is absolutely dead. Gloriously has God slain enmity, in order to save us; may we never risk the life of our souls by being resentful or by bearing grudges. We must not awaken that enmity or call it back to life by our wickedness, for it is better left dead.
No, since we possess Christ who is peace, we must put an end to this enmity and live as we believe he lived. He broke down the separating wall, uniting what was divided, bringing about peace by reconciling in his single person those who disagreed. In the same way, we must be reconciled not only with those who attack us from outside, but also with those who stir up dissension within; flesh then will no longer be opposed to the spirit, nor the spirit to the flesh. Once we subject the wisdom of the flesh to God’s law, we shall be re-created as one single man at peace. Then, having become one instead of two, we shall have peace within ourselves.
Now peace is defined as harmony among those who are divided. When, therefore, we end that civil war within our nature and cultivate peace within ourselves, we become peace. By this peace we demonstrate that the name of Christ, which we bear, is authentic and appropriate.
When we consider that Christ is the true light, having nothing in common with deceit, we learn that our own life also must shine with the rays of that true light. Now these rays of the Sun of Justice are the virtues which pour out to enlighten us so that "we may put away the works of darkness and walk honorably as in broad daylight." When we reject the deeds of darkness and do everything in the light of day, we become light and, as light should, we give light to others by our actions.
If we truly think of Christ as our source of holiness, we shall refrain from anything wicked or impure in thought or act and thus show ourselves to be worthy bearers of his name. For the quality of holiness is shown not by what we say but by what we do in life.
We possess Christ, our peace, our light
From a treatise on Christian Perfection by Saint Gregory of Nyssa, bishop
The Liturgy of the Hours, Vol. IV, Office of Readings
Thursday of the 19th Week of Ordinary Time