Literally, the sharpness of the sword is obtained from constant sharpening, and the fragrance of plum blossoms comes from its cold winter.
The extended meaning is that everything must be worked hard and honed constantly to succeed.
Literally: The sharp blade of a sword is formed by constant grinding with a grindstone. "Grinding" means grinding and rubbing. The reason why plum blossom smells attractive is that it is not afraid of the cold and has survived the winter with tenacious vitality, while other flowers have withered in winter, and only plum blossom is particularly fragrant.
Extended moral: If a person wants to achieve something in his career, he must be prepared to meet all kinds of difficult challenges, enrich his experience and improve his ability in practice, so as to achieve his desired goals. It is impossible to just want to succeed without tempering or even failing. Even if he succeeds for a while, he won't last long.