What specific event caused the US Congress to pass the Lend-lease Act?

The British need for money is what inspired the lend-
lease act.  Roosevelt's analysis was fairly telling in liking the lending of money as
akin to giving a neighbor a garden hose if their house was on fire.  In this comparison,
the "house on fire" was the threat posed by Germany to England.  Roosevelt understood
that the need to lend war supplies and money to England was absolute.  Once Russia was
invaded, the provisions of the act were applied to Russia in their fight against
Germany, also.  The single or specific act that caused Congressional approval of the act
was the recognition that Germany threatened the national sovereignty of European
nations.  It was a recognition that while the affairs in Europe were "Europe's
problems," the rise and spread of Nazism and the German nation was something that needed
to be countered and an event that possessed world implications.