Lazare Carnot was the man who is given a great deal of the credit for the success of the French armies in 1793 and 1794. In 1793, he was a military officer who was largely responsible for organizing the French army.
Right after the Revolution, there was a need for a larger army to repel attacks from various countries that wanted to reverse the revolution. Carnot was the officer who was most responsible for implementing conscription and organizing the army in ways that would allow the new recruits to work effectively alongside veterans. He was also largely responsible for logistics, arranging for the hugely increased supplies of things like gunpowder and shot that were needed. In these ways, Carnot was instrumental in creating the army that defended the French Revolution from outside attackers.