Sometimes, culture says bigger is better. It means that the size is the truest measure of success. It takes a strong person to resist that trend. This is true especially if he or she is laboring in a small place. But we must not pass by what is really great.
It's not that numbers aren't important. After all, the apostles counted their converts (Acts 2:41). Numbers represent living people with eternal needs. We should all work and pray for large numbers of people to enter the kingdom. But, numbers must not be the basis for self-esteem.
God doesn't call us to find fulfillment in the amount of work we do for Him. Also, this applies to the number of people who are a part of that work. It is in faithfully doing our work for His sake, this is the point. Serving our great God with His strength in a small way is not a stepping-stone to greatness - it is greatness. Anyone doing God's work in God's way is important in His sight. Work for Him.