Churchill tried repeatedly to convince FDR to enter the war. Instead of directly joining the fray, America sent war supplies to help Britain.
Encouraging Churchill, Roosevelt sent a letter (dated January 20, 1941) in which he quotes from Longfellow's poem, "The Building of a Ship." They were words, the President said, which applied equally to Britain and America.
In one of his BBC broadcasts, Churchill responds to the President with this heartfelt plea: "Give us the tools, and we will finish the job."
This audio clip is from that broadcast.
Audio clip, from the Library of Congress.
Text of the handwritten letter, from FDR to Churchill, referenced above:
January 20, 1941
Wendell Wilkie [FDR's opponent in a Presidential election] will give you this--He is truly helping to keep politics out over here.
I think this verse [ from Longfellow] applies to you people as it does to us:
"Sail on, Oh Ship of State!
Sail on, Oh Union strong and great.
Humanity with all its fears
With all the hope of future years
Is hanging breathless on thy fate."
As ever yours
Franklin D. Roosevelt