Grace is a mystery
I suspect that the people who use the word “grace” in the way it is used in the submitted question are expressing their amazement that their houses still stand while their neighbors’ houses are destroyed.
In their minds there is no logical explanation. This is not something that they could have expected or even had a right to expect. It is certainly not because they are better people than their neighbors. We pray. Our prayers are answered. Our neighbors’ are not. We don’t know; can’t understand why.
It is a mystery of God. Some call it a quirk of fate, but for believers, a mystery of God. It is a pleasant surprise, an unexpected present that can only be called the grace of God — an undeserved favor or gift.
Then we participate in the mystery by blessing others as we have been blessed. He helps his neighbor to rebuild his house. Because he has been given grace he now bestows grace.
Pay grace forward
We often look for explanations of good events that demonstrate to us that our existence possesses significance in the greater realm of Creation, that God favors us individually.
Many people do, indeed, as your question indicates, believe that their good fortune is a sign of personal divine favor.
But there is more to the truly religious response. To believe that you are blessed is indeed a good insight. But what is your reaction? Do you then go brag about the good news, which sounds prideful?
Or might your response be to spread the grace you have received from the hand of God by increasing the blessings you give to others?
Do you voluntarily rebuild your neighbor’s home because God saved yours? Is God’s grace a reward or a motivational lesson?
Religious people are God’s instruments, not God’s beneficiaries. Recently a friend stopped at a casino on a whim and won a good sum. He has sent at least 10 percent to a charity.
“Pay it forward” demonstrates how “acts of loving kindness” motivate others to follow suit. We bring God into the world when we magnify God’s grace to create a web of blessings for others.