Few of us have ever actually seen a nun — but many of us have seen and interacted with religious sisters.

While the terms “nun” and “sister” are used interchangeably in conversation — and both nuns and religious sisters are addressed as “Sister” — there are notable differences between the two.

Catholic nuns live in a cloistered or semi-cloistered monastery. Cloistered means enclosed; semi-cloistered indicates that while their primary focus is still contemplative prayer, at least some of the work of the nuns is outside of the monastery walls. When I attended a daylong silent prayer retreat in the public areas at a Carmelite monastery, home of the Discalced Carmelites of Philadelphia, the most fascinating part of the retreat was learning more about what the word “cloistered” really means.

During Mass in the beautiful stone chapel of the monastery, the priest walked to the wall behind the altar and offered Communion to the cloistered nuns through a window covered with a wrought-iron grating. It looked like a bank teller window from the 1940s. The nuns use a turntable called a “turn” to exchange items with the outside world. When I was there, a woman had brought a letter for one of the nuns and it was delivered via the “turn,” whereby the nuns could receive packages without seeing anyone.

Religious sisters, on the other hand, are women who belong to religious orders that work among the public. There are orders that focus on working in schools, hospitals, adoption agencies, homeless shelters, universities, and other places. It was at a university that I had my first close encounter with a sister.

I was first invited to speak at Immaculata University by Sister J. Sheila Galligan, IHM, S.T.L., S.T.D., and theology professor. The letters after her name are straightforward: IHM means Congregation of the Sisters, Servants of the Immaculate Heart of Mary, the order of religious sisters to which she has professed lifelong vows of poverty, celibacy, and obedience. S.T.L. is License in Sacred Theology. And S.T.D. stands for Doctor of Sacred Theology, earned at the Angelicum in Rome.

Her impressive credentials are dwarfed by her perpetual smile and kind demeanor. Don’t get me wrong: While Sister Sheila is a petite woman exuding gentle and persistent joy, she is not shy, but effusive and enthusiastic about God, life, love, and learning.

Sister Sheila was raised in a Catholic home but attended public grade school. She said, "I first met the IHM sisters when I attended a Catholic school in 8th grade. I had never seen sisters before! I was ever amazed and in awe. I really didn’t know anything about 'sisters' but came to sense, in concrete tangible ways, that their evident spirit of joy was somehow connected with their love for God and their being together — bonded in what they called the IHM charism."

A charism means a gift from God. When applied to religious orders, it implies a particular devotion or way members of the order are called to follow Christ.

According to their website, "The charism of the sisters is Love, which continues to manifest itself today in the sisters’ joyful service of God and his people; creative Hope, which puts all its confidence in God’s loving Providence; and Fidelity, which inspires fervor in their vocation in Christ and in their mission in the Church."

There are too many religious orders within the Catholic Church to list them all. Some are named for their founders, such as the Benedictines and Dominicans. Other orders are named for their specific work in the world, such as the Sisters of Life, who minister to pregnant women through their visitation mission.

"The next four years at an IHM high school were pivotal in my faith journey," Sister Sheila continued about her life. "I gradually came to realize my worth in the eyes of God and the call to self-gift as a means to fulfillment. Discerning a call to the religious life is a special kind of ‘adventure.’ God’s amazing work in an ordinary human life is a mystery — words can only tell bits and pieces of the story. In my case, the Lord’s voice was not heard in any dramatic way, but rather slowly. The idea of becoming an IHM remained in the back of my mind throughout junior year [of high school]."

She added, "God blessed this time by giving me a faith-filled group of friends. During senior year my relationship with God grew and I became more and more open to the thought of becoming an IHM," she told LifeZette. "I developed a love for scripture, and felt the Lord asking me to step out of my ‘boat.’"

Sister Sheila felt the desire to be a teacher from an early age. The IHM sisters are a teaching order, so she felt confident and remains so to this day that her life’s path was devised according to God’s plan.

After deciding to follow the call, she spent a year as a postulant at the IHM Motherhouse (which in 1965 was in West Chester, Pennsylvania). A postulant is a woman who is strongly considering entering the order permanently, but has not made any vows. Then followed two years in the novitiate at the Villa Maria House of Studies in Immaculata, Pennsylvania. When she professed her lifelong vows, she took the name Sister John Sheila, after her father and her mother whom she said were "ever supportive" of her life’s goals.

As a professor of theology at Immaculata University, Sister Sheila is passionate about her students and their souls. She is both teacher and mentor. Alexis Reavill, a freshman music education major at Immaculata, said, "Sister Sheila embodies the joy of being a religious [sister]. Through her examples, she challenges us to share the joy of Jesus Christ in our lives."

For me, Sister Sheila is a brilliant light in an often too-dark world. Her smile melts my melancholy and her laugh tickles my soul. She inspires me to be a better person, a more faithful Christian, and a more joy-filled witness to life.

May God continue to bless Sister Sheila and all such devoted sisters (and nuns) like her.

Jewels Green is a mother, writer, public speaker and advocate for the right to life from conception to natural death. She lives in the Philadelphia area. 

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