John-David Duggar and wife Abbie have shared a sweet tribute to his parents Jim Bob and Michelle, the grandparents to their one-year-old daughter.Posting a new picture of the pair with Grace, they captioned the post with a quote about how grandparents make the world "a little softer, a little kinder, a little warmer."Matriarch Michelle looked glowing in the picture, with her skin sunkissed, while Jim Bob held the camera and took the selfie.Little Gracie wore a big blue bow in her hair, matching