Years ago my father went to a health fair and whenever someone at a booth asked if he'd like to take their free test, he said "yes," because...why not, the test is free.
Imagine his surprise when he got a call a few weeks later from one of the groups at the fair who said, "From the results we see here from your test, we highly suggest you visit your doctor, like right now."
Dad did and got diagnosed with prostate cancer. Quickly, he went to surgery. Fortunately, everything went fine. In fact, no follow up care of any kind was needed. My family was relieved. And we thanked God for His grace.
In his book, Grace in Practice: A Theology of Everyday Life, Paul F.M. Zahl says God's grace is, "one-way love." Classically, grace is God's unmerited favor directed toward sinners. Typically, I've always thought of grace as something soothing and comforting, but when I recently sat in the ICU of a hospital with a church member who was told he needed heart surgery, I was reminded of another aspect of grace--it's sometimes scary.
When the women came to the tomb at Easter and discovered it empty--told by angels that Jesus had risen--Mark's Gospel says at 16:8: "Trembling and bewildered, the women went out and fled from the tomb. They said nothing to anyone, because they were afraid." While the earliest and most reliable copies of Mark's Greek manuscript end here with this unlikely, open-ended ending, later manuscripts add content and tame down the shocking ending.
But I think, in terms of literature and story telling, Mark's Gospel ending at verse 8 illustrates that grace is sometimes scary. It catches you off-guard. Grace exposes real problems (you have blocked arteries, you're a sinner, et. al.), but then goes on to reveal solutions (we can do surgery, you are forgiven--Christ died for your sins).
Grace is definitely comforting. It's a message of hope to a needy world.
But sometimes too, it's definitely scary.