This is a ready-to-frame Giclée print of a phrase that means "The more we sweat in training, the less we bleed in battle" in Chinese characters.
This can also be translated:
A drop of sweat spent in a drill is a drop of blood saved in war.
More practice will give one a better chance of success in real situation.
I heard this many times when I was a U.S. Marine but I had no idea at the time that it was actually an old Chinese proverb.