“Peace I leave with you; my peace I give to you. Not as the world gives do I give it to you." John 14:27

The following is an excerpt from:
Searching for and Maintaining Peace: A Small Treatise on Peace of Heart by Jacques Philippe (Author)

... we understand that the fundamental problem of our spiritual life becomes this: How can I let Jesus act in me? How can I permit the grace of God to freely operate in my life?

That at which we should aim is, then, not principally to impose a lot of things on ourselves, as good as they may seem with our own intelligence, according to our projects, etc.

Rather, we must try to discover the disposition of our soul, the profound attitude of our heart and the spiritual conditions that permit God to act in us. It is only thus that we can bear fruit — fruit that will last (John 15:16).

To the question, “What must we do in order to let the grace of God act freely in our lives?”, there is no unequivocal answer, no master key.

In order to respond to this question completely, it would be necessary to do an entire treatise of the Christian life in which one would speak of prayer (principally of meditation, which is so fundamental in this regard), of the sacraments, of the purification of our hearts, of docility to the Holy Spirit, and so forth, and of all the ways in which the grace of God could further penetrate us.

In this small work, we do not wish to address all these themes. We simply want to concern ourselves with one element of the response to the question posed above.

We chose to speak of it because it is absolutely of fundamental importance.

Furthermore, it is too little known and taken into consideration in day-to-day life for most Christians, even those who are very strong in their faith. 

The essential truth that we wish to present and develop is the following:

To permit the grace of God to act in us and to produce in us (with the cooperation, of course, of our will, our intelligence and our capabilities) all those good works for which God prepared us beforehand, so that we might lead our lives in the performance of good works (Ephesians 2:10), it is of the greatest importance that we strive to acquire and maintain an interior peace, the peace of our hearts.

In order to understand this, we can use an image (without exaggerating, as we should always avoid doing in making comparisons); but one that can be illuminating.
Consider the surface of a lake, above which the sun is shining. If the surface of the lake is peaceful and tranquil, the sun will be reflected in this lake; and the more peaceful the lake, the more perfectly will it be reflected. If, on the contrary, the surface of the lake is agitated, undulating, then the image of the sun can not be reflected in it.

It is a little bit like this with regard to our soul in relationship to God. The more our soul is peaceful and tranquil, the more God is reflected in it, the more His image expresses itself in us, the more His grace acts through us. On the other hand, if our soul is agitated and troubled, the grace of God is able to act only with much greater difficulty. All the good that we can do is a reflection of the Essential Good, which is God. The more our soul is peaceful, balanced and surrendered, the more this Good communicates itself to us and to others through us. The Lord gives strength to His people, the Lord blesses His people with peace, scripture says (Psalm 29:11). God is a God of peace.

He does not speak and does not operate except in peace, not in trouble and agitation.

Let us remember the experience of the prophet Elijah of Horeb: God was not in the hurricane, nor the earthquake, nor in the fire, but in the whisper of a gentle breeze (cf. 1 Kings 19)!

Often, we cause ourselves to become agitated and disturbed by trying to resolve everything by ourselves, when it would be more efficacious to remain peacefully before the gaze of God and to allow Him to act and work in us with His wisdom and power, which are infinitely superior to ours.

For thus says the Lord God, the Holy One of Israel: By waiting and by calm you shall be saved; in quiet and in trust your strength lies, but you would have none of it (Isaiah 30:15).

Our discussion is not, it is well understood, an invitation to laziness and inaction. It is an invitation to act, even to act considerably sometimes, but under the impulse of the Holy Spirit, which is a gentle and peaceful spirit. And not in a spirit of disquietude, agitation or excessive hurry, which is too often the case with us.

Our zeal, even for God, is often badly illuminated.

Saint Vincent de Paul, the last person anyone would ever suspect of being lazy, used to say: “The good that God does is done by God Himself, almost without our being aware of it. It is necessary that we be more inactive than active.”