Elazar Cohen's task was neither easy nor enviable when Israel was at war. He was in charge of the helicopter squad, and he and his men had to take the helicopters continually into the range of enemy fire in order to rescue wounded soldiers.
Once he went to Reb Aryeh and asked him for a blessing - and the good rabbi refused to give it. "But why?" asked the puzzled army commander.
"Who am I to bless you?" asked Reb Aryeh "I truly believe your merit before heaven is greater than mine."
This is taken from Simcha Raz's A Tzaddik in our Time.