I looked across the gym and saw Lucy, 14, running toward me, wearing a brand-new dress and stylish boots. I laughed aloud in joy as she embraced me warmly.

Sometimes we find ourselves in situations where God’s mercy has been showered upon us so abundantly, we are stunned.

This was my reaction last week at a special grandparents’ Mass and brunch at St. Thomas More Catholic School in Decatur.

I took a seat next to Lucy, while the words of a favorite hymn echoed in my heart: “Amazing grace, how sweet the sound that saved a wretch like me.”

As we waited to process into the church, grandparents mixed with the rambunctious eighth-graders, decked out in their Sunday best. The teens stood beside their kindergarten buddies, whom they’d befriended at the start of the school year.

Lucy’s 6-year-old buddy wore a glittery jacket, a dress with a butterfly pattern and pink boots. The little girl giggled triumphantly when she won a quick arm-wrestling competition with Lucy.

There I was, a childless woman who’d missed the many treasured events parents routinely celebrate. Holding the newborn in the hospital, cheering the baby’s first steps, growing teary-eyed on the first day at school.

That day, however, I savored a taste of grand motherhood as I accompanied Lucy — whose grandmothers have passed away — into the church.

In “Amazing Grace,” the words “a wretch like me” remind me of the apostle Paul, who was a terrible man before his conversion. We meet him in the Bible as Saul, presiding over the horrific death of Stephen, the first martyr.

Saul was a harbinger of terror, dragging Christians away from their homes and orchestrating their torture and deaths.

The man had gallons of blood on his hands, and as he traveled to Damascus, he heard Jesus’ voice: “Saul, why are you persecuting me?”

Everything changed then, and the man who once despised Christians becomes a defender of Christ — and humbly admits he was a wretch, a blasphemer, a persecutor and a violent man.

And he remains deeply grateful for God’s mercy: “The grace of Our Lord was poured out on me abundantly.”

Paul has a special place in my heart, because I also persecuted Christ, although on a much smaller scale.

As an atheist teaching philosophy in college, I taught my students that believing in God was old-fashioned. In my personal life, I led the quintessential “if it feels good, do it” existence.

I didn’t have a dramatic Damascus conversion, but experienced an undeserved outpouring of God’s mercy, when he called me back to him.

And despite my dark past and sinfulness, pinpoints of mercy have illuminated my path.

As I sat in the pew next to Lucy, my memory traipsed back to the Easter vigil Mass when my late husband, Jef, stood upon this altar and was anointed with holy oil as he became Catholic.

In my mind’s eye, I saw us later standing beside our friends Pam and Chris, as we became godparents to their baby girl, Sarah.

Whenever I read Paul’s letters, his words strike home, because he’s a shining example of how God treats even the worst sinners with great patience and mercy.

And in his story, there’s an assurance of God’s patience and willingness to forgive, no matter what terrible road we drove down in our past.

God really is full of surprises when it comes to grace. He has abundantly showered it upon me, despite my dubious track record — and given me an amazing blessing.

Yes, the blessing is sitting beside sweet Lucy on this special day, but it’s also knowing I have a place — as we all do — in the loving embrace of God’s arms.