I can't make out all the words, but I'm someone in the comments will. The letter reads:
Redeeming (גאולים?) Boys and Girls,
Get this blessing from the Israeli Gov't.
Learn well. Learn (למדו?) Nicely,
Tomorrow is yours!
Build a nation, Build a Country
Remez Minister of Education and Culture.
The beauty of this letter is its simplicity. I can't imagine anyone today writing to kids "Build a nation, Build a country".