What does the phrase "if you are not determined, you will not succeed for a long time" mean?

It means: to set up an ambition lies in persistence, not sharpness, and success lies in the long term, not in quickness.

1, "Be determined but not sharp, and success will be long but not fast." From: (Song) On the Body. Zhang Xiaoxiang, alias Anguo, was born in Wujiang River in Liyang (now northeast Anhui County) in the Southern Song Dynasty, and lived in Wujiang River in Liyang (now Anhui County). Shaoxing Jinshi ranked first in the court trial, above Sun Qinyu of Qin Gui. After he ranked first, he wrote to Yue Fei to cry foul. Qin Gui instructed his henchmen to falsely accuse Zhang Xiaoxiang of rebellion, put his father and son in prison, and was released after Qin Gui's death. He has served as a school bookkeeper, surveyor, housemaster, right-handed calligrapher, military counselor of the Governor's Office, Fuzhou magistrate and Jiankang. His writing style is heroic.

2. The representative works are: The Six National Anthems, Collected Works of Yuhu Jushi, All Poems of Song Dynasty, The First Ride to the Tower in Shajingzhou, Huanxi, Shuidiao Tou, Pang, etc.