We have been the recipients of the choicest bounties of Heaven. We have been preserved, these many years, in peace and prosperity. We have grown in numbers, wealth, and power as no other nation has ever grown. But we have forgotten God. We have forgotten the gracious hand which preserved us in peace, and multiplied and enriched and strengthened us; and have vainly imagined, in the deceitfulness of our hearts, that all these blessings were produced by some superior wisdom and virtue of our own. Intoxicated with unbroken success, we have become too self-sufficient to feel the necessity of redeeming and preserving grace, too proud to pray to the God that made us! It behooves us, then, to humble ourselves before the offended Power, to confess our national sins, and to pray for clemency and forgiveness.— Abraham Lincoln, April 30, 1863
Image & quote taken from here.