Much like a tree, you can tell the health of an individual Christian and a church as a whole not by digging up roots but by looking at the spiritual health of the individual. If we are rooted in shallow cheap grace, we will see that reflected in a shallow and cheap faith, one that is constantly tempted to turn away to some other paths towards salvation.
The Gospel is about grace, unmerited, disproportionate, costly grace and the book of Galatians is permeated by this idea. The church in Galatia felt this pull and Paul wrote to them with an earnest desire that they would become rooted in the Gospel that they first believed in, and that their faith would be rooted in Grace.