What is written in this monument?

Hello!

Can you tell me what is written in this monument and what it means (an historical moment maybe?)?

My friend knew I posted in the other thread and asked me.

Can you type it in?

なせば成る
なさねば成らぬ
何事も
成らぬは人の
なさぬなりけり
上杉鷹山公詠

Naseba naru
nasaneba naranu
nanigoto mo
Naranu wa hito no
nasanu nari keri
Uesugi Yōzan kō ei

If you try to do, it can be achieved, if you don't, it will never be achieved. Achieving nothing is due to one's own intention to not try.
Written by Uesugi Yōzan

That's a well-known maxim. The monument is in Uesugi Shrine in Yonezawa City, Yamagata Prefecture.

A little general advice for anyone interested in stone monuments in Japan:

Always be sure to check both sides and the rear of the stone for additional inscriptions. Often there is very useful information in those places. Also, when a stone has been set facing the prevailing winds for a loooong time and the writing on the front has eroded to the point if illegibility the sides and rear may be all you have to work with.