en_tn_condensed/gal/01/06.md

I am amazed that you are turning so quickly

Another possible meaning is "I am amazed at how quickly you are changing"

amazed that

"amazed to see that"

you are turning

Possible meanings are 1) "you are changing your mind" or 2) "you are changing your loyalty."

him who called you

"God who called you"

by the grace of Christ

AT: "because of Christ's grace" or "because of Christ's gracious sacrifice."

men

"people"