It is just like English sayings and phrases, there are Japanese sayings and phrases as well. It is called [kotowaza ことわざ].
What is the KOTOWAZA?
Kotowaza is the Japanese saying/phrases which expresses people’s wisdom and it has been told by many people from long time ago. And it is an example of something and a teachings of the life.
Today’s kotowaza
雨垂れ石をうがつ・AMADARE ISHI O UGATSU

The Origin
Even raindrops which seems to be powerless if it continues dropping on a same stone for a longtime, it is possible to make a hole on the hard stone eventually.
Its meaning
Anzuru – shinpai suru (to worry)
Yasushi – kantan (easy)
No matter how small power/effort is if you continuously and patiently make an effort it will definitely succeed.
Constant dropping wears away the stone, slow but steady wins the race, constant effort will result in success
How to use it
算数の計算が苦手だったが、雨垂れ石うがつと思って、毎日繰り返し計算の練習をした。今では得意科目の一つだ。
Sansu no keisan ga nigate datta ga, amadare ishi o ugatsu to omotte, mainichi kurikaeshi keisan no renshu o shita. Ima dewa tokui kamoku no hitotsu da. .
I was not good at mathematical calculations but thinking that 「constant dripping wears away the stone」and constantly practiced every day. Now, it is one of my best subjects.

arigato