When the previous Slonimer Rebbe encouraged a relative of his from America to study in Cracow, Poland under the founder of the Beit Yaakov movement, Sara Schenirer, he sent along a letter with this important message:
"When the Prophet Eliyahu before his passing gave his disciple Elisha an opportunity to make a request, the latter asked for double the spiritual power of his master. The rationale for such a seemingly exorbitant request was that while Eliyahu was alive his extraordinary saintliness was sufficient to influence his generation. His departure would leave the world at a lower level, which would make it necessary for Elisha to have double his strength.
You are teaching girls in Cracow how to deal with what Poland has to offer. The girl bringing this letter needs to be armed with much more in order to stand up to what America 'has to offer'."
That girl eventually returned to America, married a distinguished educator and gave birth to Rabbi Shimshon Pincus, zatzal, who influenced a whole generation.