If we drop a stone in a body of water it creates waves that spread outward, and continue until the force subsides.
But what happens if we continue to drop a stone into the same place?
Now think of it as a single person doing an action such as helping someone in need and that wave continued to the next person and then the next and so on.
Then each person the wave touched did the same, which created another wave of goodness. How far could this single act reach.
Every time you or someone else says I’m only one person, keep this thought in mind.