It is common for Christians to make a call for people to get involved or sign up to serve or even to give because there is a great need.
And there is a great need!
However, if the need is the only basis you ever use for that call you will usually get only average responses. When things are simply “needs” they only need simplistic solutions. Stop gaps. Temporary fixes.
However, when you call people to be involved in something massive, something’s that will matter and make a difference, you might get fewer people, but you will get more invested people.
It’s the difference between, “hey, we really really need Sunday school teachers or else the class can’t run” and “hey, there are 10 kids you are like sponges every Sunday, and you could be one of the people they thank God for putting in their life when they are 60 years old.”