The fact that pen has greater strength than sword has been proved through ages.
The meaning behind this saying has great importance. It means that knowledge and intelligence have more power than just strength.
A learned and intelligent person can find a better solution to a problem than the one having only physical strength. We can see from everyday life that an illiterate laborer has to work very hard to get something. But an educated person uses his mind, works intelligently and with less energy to get more than the laborer.
The sword can only do aggression and destruction but the pen can find a peaceful solution to the problem. The man having the sword has to repent on what he has done, but the person having the pen is successful and happy in the end.
An example from history is that when a king was coming with his ships through the sea to invade a country, a great scientist of the country, which was invaded, reflected the strong bringing rays of the sun by mirrors towards the ships and burnt them.
Even in our daily life, we see that sitting and thinking coolly .can find than the solution to a problem through vigorous foolish action.