Love between two spiritual beings demands a union of wills. This statement refers to the human soul insofar as it understands, desires, and pursues the purpose of its existence; it is the depth of one’s being that gives meaning to what constitutes his personality and way of acting.

The relation of love between God and man implies that at every moment and in every circumstance man seeks what God wants him to do, and he does it.

How can man know what God’s will for him is? First of all, through the Ten Commandments, the evangelical counsels, and the general directives found in Scripture. In addition, through such events in our lives that God wills, permits, or tolerates. This Providence of God watches over all people, and so it pertains to everyone in general.

But there is something more for each one of us, a particular will of God covering each moment of our existence. How can I know it? It makes itself known to me at the very center of my being by an imperious yet whispering call inviting me to choose this line of action in preference to all others. Undoubtedly this call is the natural reaction of my conscience as a person before a situation in which I find myself involved, but because I am a Christian the call is also the reaction of a conscience enlightened and strengthened by grace. The voice of the Lord, so to speak, is within me by virtue of two different conditions. It is there first of all as the judgment of a human conscience, and at the same time it is there as the motion of baptismal grace. This call is usually referred to by spiritual writers as the “inspiration of the Holy Spirit”.
The place of such inspirations of the Holy Spirit in the life of a Christian is therefore considerable. It is through inspirations that God informs me at each moment what his will is for me here and now. For the Christian the dramatic debate between good and evil, which takes place at the center of every conscience, consists of consenting to or resisting the inspirations of the Holy Spirit.

Let us hear what St. Francis de Sales, an expert in this field, has to say about this subject: “After God had formed man from the clay of the ground, … he breathed into his nostrils the breath of life and made of man a living person [Gen 2:7]—in other words, a soul that gave life, movement, and activity to Adam’s body. The same eternal God breathes, infuses into our souls the inspirations of the spiritual life, so that, in the words of St. Paul, they become living souls [1 Cor 15:45]—in other words, souls that give life, movement, feeling, and activity to the operations of grace.”St. Francis de Sales, The Love of God, 340. In this manner inspiration is as necessary to the life of our soul as breathing is to the life of our body. How does it function? “By inspiration”, again writes St. Francis de Sales, “we mean all those interior attractions, movements of the heart, pangs of conscience, and illuminations of the mind by which God, in his fatherly love and care, predisposes our hearts with his blessings, to awaken, stir, urge, and attract us to virtue, charity and good resolutions, in fact to everything that serves our eternal good.”St. Francis de Sales, Introduction to the Devout Life, 76. Inspirations therefore play a major role in the continuous struggle between good and evil that goes on in a person’s conscience. They form an integral part of our spiritual life.

It would seem that for a generous soul the way leading toward the good should be clear and simple, that it would be enough for him to follow the motions of the Holy Spirit. The fact is, however, that the process is far more difficult than it would appear at first sight. The soul itself is subject to illusions, and Satan, in order to carry out his intrigue, can at times transform himself into an angel of light. Given this fact, the following bit of advice from St. Francis de Sales is extremely valuable: “Before you consent to inspirations concerning important or extraordinary matters,” he writes, “seek the advice of your confessor, that he may examine whether they are true or false and so preserve you from deception; for the devil often sends false inspirations to deceive those who receive them readily, but he can never deceive those who humbly obey their confessor.”St. Francis de Sales, Introduction to the Devout Life, 78. Elsewhere he repeats a few words full of wise advice, which he has already given in the eighth book of The Love of God, on how to recognize “legitimate inspirations”: “It comes therefore to this: the three finest, surest proofs of the genuine character of inspiration are perseverance in contrast to fickleness, peace of soul in contrast to impulsive anxiety, humble obedience in contrast to stubborn willfulness.”St. Francis de Sales, The Love of God, 351.

We can better appreciate the rules St. Ignatius gives for understanding, analyzing, and appreciating the different movements that can take place in the soul of the person making the retreat when we see them within the general framework of the role inspirations play in our spiritual life.