Yes, it is true! An act of charity & kindness does go a long way! Let me explain it to you! When you help someone who is in dire circumstances and needs your help desperately, you save that person from disaster.
Now, this person nurtures good feelings about what you did and that has a significant impact on his/her mind. The impact is vaster and greater than your imagination. Your one act of charity & kindness may completely change a person – making him/her also helpful and compassionate towards others.
The entire process is like a chain reaction where you touch one person with generosity and then the process just goes on and on forever. In short, your one good act may bring about complete change in society.