Is there anything we can do for people around us? Think about the many relationships connected to you, and a time when you went through a rough time. The kindness you received at that time must have still been in your memory. Kindness is never forgotten. Therefore, we need to be kind to others.
The quote by Plato says that everyone is fighting their own battles, and that is why we should treat each other kindly. It may sound like you should have excessive maturity despite enduring a difficult battle. However, if you are immersed in your own race, you may hurt your neighbors and pass their difficulties carelessly. No one should be subjected to self-centeredness, because some day you can be a victim of it as well.
What kind of battle of life are you in now? Or, do you remember the kindness you received during your past battles? Even if you are fighting so hard that you want to give up now, you can always be kind by remembering the kindness that remains in your heart. Remembering a warm heart will help you endure the tough and harsh times in your life.
The persons beside you now need your kindness. You should be kind to those in need of your kindness. Your kindness, even in the face of harsh battles of life, will become a significant source of strength to them. Likewise, I will gain the strength to live by recalling the kindness I have received from others.