How do I know if a call to religious life is from God or just my imagination?

I have to begin by quoting Joan of Arc in George Bernard Shaw's wonderful play about her trial. When Joan's interrogators doubt that the voices she hears are from God and suggest that they spring from her imagination, Joan replies as if her accusers are hopelessly ignorant: "I know. That is how God speaks to me."

We tend to belittle the imagination as the realm of children. We forget that Jesus had a high opinion of children, favored their company, and thought we should be more like them: "Of such is the kingdom of heaven." Many saints agreed with Joan's assessment that imagination plays an important role in the spiritual life. Teresa of Avila, no slouch about spiritual matters, employed religious imagination deliberately and recommended it over theological reflection: "I continued to picture Christ within me. . . . I did very simple things of this kind. . . . I believe my soul gained very much in this way, because I began to practice prayer without knowing what it was."

It's safe to say that the call to religious life most probably begins in the imagination and in no sense does this imply that it's to be ignored. But obviously if any vocation remains in the daydream stage—whether it's about becoming a bookseller or a Benedictine—it won't progress far. I would advocate three tools in the early discernment stage: regular prayer, reading, and retreat. How you pray best is up to you, but make it a habit. Daily mass attendance, praying the rosary, the liturgy of the office, meditation on the Bible, or using a daily prayer guide from your local Catholic bookstore may help.

Reading is next. Read about topics like chastity and celibacy but also about the specific aspects of the vocation that interests you: contemplation, ordination, communal life, or a particular form of service. When you're ready, schedule a retreat and ask for a spiritual director. And remember Joan of Arc's prayer about being in God's grace: "If I am not, may God put me there; and if I am, may God so keep me."

Scripture
Matt. 18:1-5; Mark 9:36-37; Luke 9:46-48; Ephesians 4:11-16; Philippians 3:12-15; Colossians 1:9-12; 1 Thessalonians 5:16-24; 2 Thessalonians 1:11-12

Books
Becoming Who You Are: Insights on the True Self from Thomas Merton and Other Saints by James Martin, S.J. (HiddenSpring)
Finding God in Each Moment: The Practice of Discernment in Everyday Life by Carol Ann Smith, S.H.C.J. and Eugene Merz, S.J. (Ave Maria Press)