These two matters are well worth attention:
We have noted another point: not to ask any more than God allows. For even though he bids us pour out our hearts before him, he still does not indiscriminately slacken the reins to stupid and wicked emotions; and while he promises that he will act according to the will of the godly, his gentleness does not go so far that he yields to their willfulness.
Calvin, Institutes, III.XX.5
