That's one of the most efficient ways to force your body to make incremental adaptations, i.e. build new lean muscle tissue so make the most use of it. (fitnessandpower.com)
Protein provides the building blocks of muscle tissue to aid both the creation of new lean muscle and to aid recovery of what is already there. (womenshealthandfitness.com.au)
The best of all is that resistance training will help you even gain new lean muscle while you're cutting, as long as you're getting enough extra protein. (fitnessandpower.com)