This is one of the most common things I hear from people who are not vegetarians. They believe that it is impossible to get protein from eating just vegetables. This is not true, of course. There are many ways to get protein from plant sources.
For example, some of the strongest animals on the plant are essential vegans: Gorillas, Horses. These animals don't need to eat steak to eat meat.
The truth of the matter is that you can get plenty of protein from green vegetbales. You can also get most of it from legumes. Most of the world eats rice and beans in some form and that is where they get their protein from.
If you look at Asia, Indian, Mexio, these countries have people who subsist on beans, peas, or lentils and rice. This is perfectly acceptable and gives them all the protein they need.
Other sources are foods like quinoa.
Here are some good recipes from All Recipes that focus on the protein found in non-meat recipes.
http://allrecipes.com/howto/13-high-protein-recipes-for-vegetarians/
