## 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"