:::Man is most ungrateful, if...he do not acknowledge divine grace.:::
Harley, you’ve got to follow the sentence through.
The sentence states that man is most ungrateful IF he does not acknowledge divine grace. That says that man has a choice, which is nothing that Calvin ever claimed.
Not quite correct. Actually Calvinists believe in the will of man. That will is held hostage, unable to acknowledge God. God must set that person free.
As Ireaneus points out, and one that I would agree with, man is certainly most ungrateful if he cannot acknowledge what God has done. That being said, I would also add that it is impossible for man NOT to acknowledge what God has done for them.
Do you think a saved individual cannot acknowledge God's gift? Do you think an unsaved individual can acknowledge God's gift?