You won't give up until you've hit a wall — only then will you turn back.
Tips
history
Recorded in the late-Qing novel 官场现形记 (Guānchǎng Xiànxíng Jì, 'Exposé of Officialdom') by Li Baojia. The Yellow River (黄河 Huáng Hé) is figured as the ultimate barrier — until you literally reach it, you keep believing you can press on.
usage
Often paired with 撞了南墙才回头 ('only turning back after hitting the south wall'). Can be admiring (perseverance) or critical (stubborn refusal to face facts) — context decides.