It should be to praise others for being young, knowledgeable and knowledgeable.
Allusion: During the Eastern Jin Dynasty, Chen Wang, a young official, visited his uncle and scholar Fan Ning. Zhang Xuan happened to be at Fan's house. Zhang Xuan assumed a doyen posture and wanted Wang Chen to give him a gift, but Wang Chen ignored him. Fan Ning blamed Wang Chen and thought that the old-timers should be modest. Fan Ning thinks that Wang Chen is young and knowledgeable, and he is really a rising star.