“It is very apparent from the Word of God that he is wont often to try the faith and patience of his people, when they are crying to him for some great and important mercy, by withholding the mercy sought for a season; and not only so, but at first to cause an increase of dark appearances. And yet he without fail at last succeeds those who continue instant in prayer with all perseverance and ‘will not let him go except he blesses’ (Genesis 32:26).”
In other words:
An obvious pattern in the Bible is that God tests the faith and stamina of his people as they cry out in prayer for some significant mercy. He tests them by withholding the mercy they are asking for. Not only that, but first he makes things worse, sending them discouraging setbacks. But count on it—he will eventually prosper those who push through in urgent prayer without quitting and will not take no for an answer.
Jonathan Edwards, “A Call to United Extraordinary Prayer,” in Works (Edinburgh, 1979), II:312.