The meaning of calligraphy of working hard and moving forward steadily and far away

It means that only by moving forward bravely through training and being down-to-earth can you go further.

Hard, the original meaning is a whetstone, and by extension it means tempering. To forge ahead means to forge ahead bravely through training. From "The Classic of Mountains and Seas·Western Mountains"

Going steadily and going far means that if you want to go far, you must first go steadily.