Walt Whitman said this.
It's a great reminder of how to approach other people who think differently than we do.
Rather than react with our typical (and natural) need to correct other people whom we think are wrong, we can try to figure out what they're thinking and why they're thinking that.
It doesn't mean that we have to change our way of thinking, but it improves the way that we can see something. Even if the other person offers a perspective that we disagree with, at least we can come to understand what caused them to have that viewpoint.
As an interesting example, one friend posted a message on Facebook promoting Bernie Sanders. Another friend, a retired marine and police officer, spat that anyone who votes for Bernie loses his friendship because this person sees it as an affront to the military.
The first friend was pro-Bernie because they believed in the idealistic messages about helping people with living and healthcare needs, not because they were anti-military. However, the second person took this personally - he's put his life on the line for this country multiple times, and saw the message as a slap in the face.
It would be so unfortunate if these two people lost their friendship because one or both heightened their animosity rather than trying to figure out the common ground.
So too can this happen in the world of work - whether it's just about getting along with co-workers or understanding an approach that someone wants to use for fixing a problem or improving a process.