The couple referred to newborn baby Jacob Bryan as a "miracle" in separate posts on Instagram in light of the loss and heartbreak that preceded the birth —the "Cry Pretty" singer revealed in September that she suffered three miscarriages over the last two years.
"You are a gift from our Lord!" Fisher wrote Thursday with a closeup picture holding Jacob Bryan on his chest. "The last few years has had its challenges and it makes this moment even more sweet! We didn’t know if Izzy would ever have another sibling but we learned through it all that God is in control and his timing is perfect! He is good all the time even in the difficult times that are hard to understand."
Jacob's brother, who is 3, is called Isaiah "Izzy" Michael. Both Jacob and Isaiah are popular names from the Hebrew Bible.
Jacob, whose name was later changed to Israel, was the father of the 12 tribes of Israel, and Isaiah was a prophet who is credited in Christianity with many messianic prophecies.
Their middle names compliment their family. Michael after Mike and Bryan reportedly for Carrie's family.
The American Idol winner and the former Nashville Predators hockey player have never been shy about their faith. Fisher told Oprah Winfrey it made for an "instant connection" when they first met.
"We both grew up in Christian families, and kinda experienced life, and all of a sudden it's fame," he reflected. "Spiritually we're kinda able to be on the same page and understood each other. And now, it's a big part of our marriage, for sure."
Underwood has said the couple prays regularly and tries to read the same Bible study material so they can discuss it together.
The "Jesus, Take the Wheel" singer has also been instilling her same faith in Isaiah.
“Mike and I talk about teaching him how to approach everybody in a loving way, even if they’re not the same, and to try to say, ‘You know what? God loves them, so it should be my job to do my best to love them as well.’” Carrie told People Magazine.
In 2017, she posted an adorable duet with "Izzy" singing "Jesus Loves Me" in the car.
Underwood's faith is something she's put front and center - singing hits like "Something in the Water," "How Great Thou Art," and "Love Wins." It's something she strongly defends as well.
"Country music is different. You have that Bible Belt-ness about it," she told Glamour in 2012. "I'm not the first person to sing about God, Jesus, faith (or) any of that, and I won't be the last. And it won't be the last for me, either. If you don't like it, change the channel."